I would expect the river shove to be pretty nutted, so the fold here seems fine to me.

Indeed, I think if you decide to bet on the turn you can start polarizing more, ie use a larger bet sizing. But note that, in my opinion, both on the flop and on the turn a checkback is a good option some of the time (and dependant on villains play style).

Totalemente fine

Seems ok. This line (x/c x/c lead) is underbluffed, at least in my pool. He has all AJ (we block some yes), he has KQ/KT/TT/44/flushes. My pool will have QQ/KK here sometimes.

We have AA/KK/QQ/TT/AJs at least. We have some flushes so letting this go here is ok I would think. Checking flop some of the time here also and this seems like a good candidate to strengthen up my checking range.

good fold

Good Reg, ok reg or fun player?

I’d never call an ok reg. I think good regs are usually but not always underbluffing.

Fun players bluff or overvalue hands here the most. I think it’s near to break even.