I was thinking more about the bomb calc and talked it through with some people, and here’s what I came through.
Vine would not fully scale to the bomb since the explosion greatly expanded the bubble he made. However, by the sheer fact that Vine was able to create the bubble in the first place that had enough power to halt the bomb, he should downscale easily. While he did die, theoretically, he could pull out that amount of power anytime he wanted to. Again, it was the ACT of creating the bubble, a construction feat, that boosts his AP, not the fact that he died from the explosion.
Furthermore, Team RWBY should easily scale to this due to the fact that they are able to contend with maidens, who are narratively stronger than anyone in the setting, including Vine. After all, Weiss was able to survive a blast from a bloodlusted Cinder, as well as Winter surviving an assault by Cinder too. And in both instances, they had no aura. Thus, this makes the scaling easier.
Again, I am not saying that Vine scales to the full yield of the bomb, since the bubble he made got stretched out. But he should still scale to a good amount of its yield. Where the AP comes from is him creating the structure that can contain the bomb, which he can do WITHOUT dying.
Lastly, no where is it stated that vine’s aura arms are any tougher than his regular aura. He just states that it is an extension of his aura.