Hi, Michael2345!
I will try to state my point shortly:
-for your first question:
-we need to know what range villain is raising with and what range he is gonna call on a re-shove. That's really all about it. It could be tricky though and it's hard to master it. We need great sample and once again-villain can adjust to our adjustment. If we are in the 12-24bb eff. range, I will generally re-shove every hand that I want to play against the late position raiser. However, sometimes, say villain has a very wide stealing as well as very wide calling range(maniac fishes), then we can't profitably 3bet shove hands like JTs or 89s. But they do good vs villain's perceived range and if we get good odds on our flat, I will just flat and go from there. This requires a bit better postflop and hand reading skills though.
Second question-so many different scenarios depending on board structure, risk aversion, eff. stack sizes, opponent's tendencies...I can't really cover all the possible incomes.
What's best to do is post hands in our hand evaluation forums every time you not sure how to play a certain hand.
Cheers!