This implies ("prefer...galvanized") that more Gen Z people are doing ICE protests than did No Kings et al. Is there any reason to believe that's the case, even just in the cities with large scale ICE presence/facilities?

The floor keeps delegates from going to fringe candidates, but withdrawals also create a pool of uncommitted delegates, some of whom get reallocated based on state rules.

Delegates are allocated within states proportionally, and then they do the actual voting for the pres nominee at the convention. There is a 15% floor to receive delegates, but some states also do the awarding within congressional districts so it gets complex.

I agree in general, but what's the advantage of RCV for presidential primaries when they already proportionally allocate delegates? The handful of states already doing it eliminate at a 15% threshold, but similar is true in non-RCV states for proportional allocation.