I'll start off with each example individually.
The Kid Buu/Vegeta example.[ This one is odd to me as you yourself admitted this be interpreted differently but say it's proof of soul damage. However the problem is it's not specified that Buu is doing the soul damage himself. What I mean is that another interpretation is that since Vegeta is already dead, just rocking a physical body, the laws of the Dragon Ball world dictate that he'll simply cease to exist. Goku simply says if you die while being dead, he's speaking universally, not specifically to dying from ki based assaults. This is not to say your interpretation is completely invalid, I'm simply saying there is another alternative that explains the example that doesn't require Kid Buu effecting the soul. (Basically I'm saying that Vegeta "could" have died from a heart attack while in that state and he'd cease to exist given the description Goku gave)
First off, thank you for actually taking the time to read and address everything. Very much appreciated. Now, for your hypothetical of vegeta dying another way, like a heart attack for example or natural causes, I definitely see what you are getting at with this. While it is true that goku is speaking universally about this specific instance of dying while dead, in context, I think it's more consistent to think goku means like actually being killed by another while dead. As yes, it is interpretation based to an extent. But in these instances we would go with the most likely/most consistent. But I can definitely see your argument, I won't argue about this point too much.
The Frieza example. The afterlife constructing a new body for Frieza doesn't mean everyone's soul and body regenerates because it's not implied everyone's soul is getting fragged. Frieza just gets a new body in hell to be tortured, otherwise everyone's body would be regenerating but we know that isn't the case given we see many individuals are those little clouds. I don't find this supportive to the Vegeta thing since I explained how that can be interpreted differently above.
On this point, I never argued that souls that die all get fragged. That was more so an example of that actually being possible and it not breaking any rules, which is why I brought up the moro examples. Also, frieza doesn't inherently have to receive a new body to undergo torture, since souls have a consciousness, retain memories, and their mind. Frieza really has no reason to have a body, and yemma has no reason to give him one either. Frieza was actually an anomaly, he refused to repent, and as such, was forced into a cocoon, his body totally useless. Also see the raditz example I put out. Raditz would of had to undergo some sort of regeneration/healing after he got a beating from king yemma, which supports the argument. So, I think you'll find arguing these points from the perspective of ki damaging the soul, takes far less assumptions, than it would if you were to argue the latter, that being ki does not damage the soul. At least not passively.
The Yamoshi example. The issue here is that it just doesn't say how damaged his soul was, it doesn't mention his death as in was he beaten to death or blown to pieces? It just mentions he's a wondering soul. Using the Moro saga as an example to prove why his soul didn't regenerate doesn't work when his soul wasn't mentioned to be damaged in the first place, let alone to what extent. I just don't see this as much of an example given the lack of context.
This seems kind of weird to me, since you did admit that my example with the ki/hakai point technically wasn't disproven. So in this case, its not a matter of IF his soul was damaged. It seems you agreed it was, so what matters is
how much. Now its true we don't know how much his soul was damaged. But remember, I only used the moro scan to prove how there would be no issues with yamoshi's soul being fragged and still being able to commune with other spirts, not that it absolutely was fragged.
The Vegeta/Moro example. I guess this works given it's not stated Spirit Fission is what allowed Vegeta to interact with Moro's soul, more so the technique is allowing him to split it from his body. Thus I can concede that this is valid proof since the the spirit stuff for the Yardrats is equivalent to ki.
Okay great, we can move on then.
The Granolah example. This honestly just seems like a drawback of his cloning technique. It's not mentioned that because Gas is hitting the soul that Granolah takes the damage from the others, it's simply said that the damage done to clones is felt by the original. This is just the techniques side effect as many cloning techniques have different drawbacks in fiction. If that statement was said in any other verse we'd assume it's the technique's after effect but your argument is because they can hit the soul, Granolah took the damage, which isn't explicitly mentioned. I'd go with the basic understanding that is a side effect of the technique.
Now I'm going to put a lot more emphasis on this response since I do have some problems with your counterarguments against it. Now, you are correct in your assessment of Granolah's ability. That being the drawbacks. But it's a little more complicated than that of course. In order for these drawbacks/side affects to take place, it depends on prerequisites. The only one that is, is for his clones to actually be damaged. There is a difference from a technique taking a physical toll on you JUST because you used it, as opposed to the side affects happening because of a certain condition taking place. Let me explain. Now again, what exactly are granolah's clones? Well they are simply his own
power/ki/soul, that's it. Since ki=spirit, he takes some of his own
actual spirit, and manifest it as clones to fight for him. They are capable of using his own techniques, his own mind, capable of talking, having conversations, etc. Pybara explains how they don't devote any of their time
anywhere else but spirit control. Which is exactly what Granolah is using, just splitting his soul. Now, what is important here is how granolah's clones actually get damaged. Gas attacks granolah's clones with
physical hits, and just basic
ki blast and beams. That is exactly how he took so much damage. We know this energy fizzles and goes back to granolah, which is exactly why he
retains the damage. For this to be the case, this means gas is just straight up interacting and harming granolah's soul. Again, it really needs to be understood that the clones are literally just a result of
splitting his very spirit, which adds more validity to the overall argument I'd say. That is the only way it can be explained for this. The damage sticks to his ki/soul. It is a drawback yes, but this only exist because of how the technique actually works.
My overall thoughts regarding this will be mentioned below.
My Overall Opinion and Stance
I can see what the OP is trying to suggest, I do agree that Ki has soul damage properties. The strongest evidence I think is the fact that yes, at its core Hakai is still Ki, it's not mentioned that it's because it's Hakai it's what allows it to interact with the soul, the same goes for Spirit Control as it's stated to just be the equivalent of Ki. So given Ki possess spiritual properties via the various methods, I can agree that it can be used to damage the soul.
However, I don't think it's a passive like effect that they're doing all the time. Hakai, Spirit Control and their applications are outright naturally applying that spirit aspect. I'm not saying they're fundamentally different, I'm saying there the application being utilized. Hakai is pure destruction, Granolah defined his version as a "Technique", Spirit Control/Spirit Fission is Vegeta applying the spiritual aspect of Ki in a harmful way. These are clearly displayed as methods to apply the impact of the spiritual aspect of Ki. The verse wouldn't describe them as such if every random who threw a ki blast was immediately applying the spiritual aspect of soul damage.
So while I agree with soul damage being a thing, I think it should only be applied to the ki energies or techniques of characters who tailor their attacks to go that route. I'm not saying it's not a function of Ki, I'm saying it's an aspect that they have to apply, not a passive one. They can hit the soul but I'm requires them to attune it to do that. I just don't find most of the supportive evidence solid enough to say it's a passive effect of basic ki attacks, I think some of them can be interpreted differently which leads to a less solid argument. Now this doesn't mean it can't be what you're saying, I just see it differently specifically some just being laws of the world or technique.
I'm sort of confused by what you mean here. Are you saying you think this is something that like, consciously has to be applied by ki users, as opposed to something that just
happens? If so, how do we treat this? Because it seems like you're saying its situational, which I'm not sure how I feel about that assessment. How would we know when this specific property is applied? And is this more accurate than saying this just always happens as simply a product of being ki itself? Especially since ki is just spirit in general. Hence, I feel like that would be more consistent, and require far less assumptions such as that. Let me know if I have something wrong here. If my responses don't change your mind to this, feel free to correct me of your intentions with your statement.
I guess the resistance to soul damage can be universal since that's not something they seemingly need to attune, given characters with no Hakai, have resisted it's effects if strong enough.
Okay great, well that doesn't need to be discussed further then.
Anyway, those are my general thoughts on the matter. I've still got IRL work to do so I might not respond to any comments quickly.
Yeah all good.