I don't expect many villians to 3b the flop w/ diamonds unless it's exactly 87dd, there's an outside chance he has 9xdd or QJdd but I'd say your behind OTT close to never. You have just over pot left so just jam the turn to protect your hand and for value. You want to force him to make a big fold or losing call with his sets and I expect most really bad players to do the latter.

Dont think there are too many FD's in his range as played, something like QdJd it would make sense. Also, if u dont know the player, if its an occasional player he could also be doing this with many overpairs nd some sets. Too many hands in his range that you're beating in turn.. We dont have any other decision  than just shoving...

Very difficult hand. I think we have some options here after flop: He can have 2 diamonds, a set, JJ, AT, KT, QJ, QT, JT, 88,77 . I think he wouldn't call your reraise with any of this hands but two diamond cards and QJ, 77 and 88. Since you have already two blockers, for me he hits a flush or he misses the QJ straight on the turn. Since you don't know and he has position, i would just check/fold most of the time. Shove, for me, is not a very bad move, since you don't want to see the river 

If my brain is working, you have 13445 effective on the turn with 11535 in the pot.

I think betting like 3.5 is fine here? Not quite sure if shoving is best because his range folds everything except what beats you. I'd be more worried on a board pairing turn given the action on the flop. 

I think 3.5k and shoving blank rivers, but ch/f when the board pairs or maybe if another diamond rolls off. Depends on villain with a diamond because I expect his only diamond to be 99 with a diamond, or QJdd (maybe not even this because it's a weird line to take with that much equity - 3b flop but flat a 5b? He would just shove it vs the 5b or flat the flop 3b), and not all players can value bet that given you think he is slightly weaker player and on a four flush board.