Nut flush draw & nuttin' else -- flop and turn play

I think you can go ahead and bet flop with nfd + 8, hoping to get there or get folds by river.

Turn potting seems very spewy idea, you're repping 97 only that potted straightboard. You're not blocking 2 opponents having that 7 but are blocking spades. Against obviously call happy opponents I think this is just wasting money.

you will get better spots to bluff there,
Flop:
1/ cbet pot, stacking off vs reraises...
2/ check/raising flop... we have NFD,blocker to the nuts, and a ton of fold equity.
Turn:
paird board, i am not sure to be honest, I know if I held a 9, I would continue, 88,TT, I continue, but vs 2 callers, oop, we better give up. because if you bet now, you should at least make sure that you have about potbet behind on the river so you could bluff... UTG is a shorterstack (1,40$ starting the hand)... he has already less than a potbet on the turn...
I would give up oop.

Flop
I dont have templates for limping ranges but assuming they limp-call worst 10-15% of their 25-30% vpip (weak players rarely limp-fold), one of em hit a straight 13% and a T8 or better nutstraightdraw 21%. I would not care too much about the straightdraw because the possible flushdraw is devalueing their straightdraw and giving them reverse implied odds on possible runouts. I also dont think they would start raising a bare straightdraw 3way. We cannot bet too big as we have no range advantage, we are not holding 86 more often than villain, but still want to generate some foldequity so bet 50-67% so a dominated flushdraw could call and pairs that have us beat may fold.

Turn
The pairing 7 is a pretty bad card as, we could be drawing dead already and does not function so well as a scare card to bluff weaker players. loose or weak players would call again with with an overpair or toppair+sidevalue. Trips and boats have u beat now. I would just checkfold, considering both players called and there is 1 street left to play oop where u are in a difficult spot oop against unknown opponents, probably -EV.