Would it be possible to add a Mr. Hippo%? (to see the fastest to activate his monologue) If not, what about a DeeDee%? (to see how fast can someone get her to add a new challenger?

That is completely luck based and involves no skill whatsoever

Speedruns are meant to test your skill at the game, not leave it all sup to RNG. That's the point of speedrunning after all, 1% luck 99% skill