Table is pretty loose and gambly, hero has been at the table for about 3 hours.
V1 - BB ($130) Sat at the table about 30mins ago, has been playing very passively. No real reads on him thus far.
V2 - UTG ($600) Been at the table before hero sat, been gambling with him throughout, with straddles and double straddles. Doubled hero up when we both had sets. Couple of hands later hero doubled him up when he called a 3b pf and flopped a flush draw with Q3s.
Hero - UTG+1 ($700)
V3 - UTG+2 ($190) Just sat down hasn't played any hands so far.

On to the hand, V2 raises to 12 preflop, hero calls with KJhh, V3 and V1 call. 1 other calls as well.

Flop ($61) - J 7 3
V1 checks, V2 checks, hero bets $37, V3 insta min-raises to $74, V1 calls and V2 tank-folds after a long while. Hero?? Fold or shove?

I'd be inclined to fold here with no information or reads on V3, a min-raise into 3 other V's by V3 is more than likely a sign of a MONSTER such as a set of threes.

In the OP you described V1 as playing "VERY passively" so could quite easily have you dominated with AJ if he's calling a re-raise OTF OOP if not then more than likely he has NFD with two overs or KQcc as he's more often than not going to be playing his draws passively if he's a "very passive" player.

My advice in this spot would be to FOLD. In the wise words of Phil Galfond: "Rarely is it a HUGE mistake to fold."

We get check/raised and cold/called?

Yeah, Im done with the hand.

Hand is well played if you fold now.

I think this is a very easy fold pre-flop. You should be calling UTG raises when you're UTG+1 with a much tighter range than you would be open raising UTG+1.

On the flop you probably have over 50% equity against betting hands. I think it's a clear check-call.

As played it may be a fold, but it's one of the situations I talked about in a recent thread: If you ignore implied odds if he hits and you fold over 3% of the time Villain only needs a gutshot draw for this to be a profitable spot for him.

Preflop is debatable but not necessarily bad. Consider 3betting sometimes if you're the button.

Flop is a standard fold after getting c/r'ed and flatted.

You want to play the big pots with sets or a 5-card hand, not a 1-pair hand.

I could conceivably isolate V2 in position, but a call isn't awful.

After a x/r by an unknown and a cold call though, I'm done with the hand.

Without any reads on V3 this is a tough spot. You're either way ahead or way behind. He either has AJ, 2p or a set. 77 would make the most sense. Although, why would he min-raise a set? He might try to get more value out of it. There are a lot of draws out there.

I'm more aggressive so I would probably lean towards a shove in this spot. I think either line you take is OK though versus an unknown villain like this.

Just gonna throw this out there and why I disagree with this statement... at my games a min-raise of any substantial bet post-flop is nearly always the nuts or darn close to it. A check-min-raise is ALWAYS the nuts...and if the opponent tanks before min-raising or looks all "confused" before min-raising, then it's REALLY the nuts.

Sure, some high-level thinking opponents might level ya every now and then with a draw or something, but in my humble experience tossing away almost all of one's range after being min-raised is the way to go.