You know, this is reminding me of the list of Liger686 calcs of Ben 10 and how most of them are only tier 9, but we still accept the Tier 7 feats anyway. Yes, I know it's because there's enough of them (as is the case here), but using the argument that they should be 9-B because they keep getting harmed by 9-B attacks is kind of weak. We'd probably have to downgrade a lot of verse with that kid of logic.
Freckles didn't
just shake the ground, they did so hard enough to cause a cave in from quiet a distance away, which, assuming the rock was already weakened, would take a
Magnitude 4 or 5 earthquake. And yes, I am talking about radiated waves (physical strikes) in that case.
Last I checked, the problem with RWBY was that there were only 2 8-A calcs, but one of them didn't hold up under scrutiny,
on top of the number of 8-C feats.
Also, regarding the skyscraper, considering just how massive it was in the first place, that Sharkface even survived at all and could stay alive under all of it for what must have been at least hours (since they would have to dig him out) is noteworthy in and of itself. I also did a low balled calc (not posted) of what it would take to survive getting crushed by the Empire State building and it came out 8-A.
Lastly, regarding my calc, it already accounts for the multiple explosives needed.