I have a conclusion S that is moderately interesting. While the corollary of S is more interesting, the corollary of the corollary of S is extremely interesting. Should I just label them corollary 1 and corollary 2 or is there a better way of handling that?
It's a judgment call... For example, if S is not really interesting by itself and there's a little work in going from S to its corollary, then it might make sense to call S a lemma and its corollary a theorem. But it's perfectly fine to have two corollaries as well. None of these options are technically incorrect, they're just signals to the reader about what role you think they play.