I have had a much better think about this hand and looked at it using an equity calc.here is my take on it...
As we don’t have stats for the hero or villains I assume for the analysis they are solid regs
Vinyl opens UTG JTs, most solid regs at 6 max open about 7-9% of hands. If we give V a typical 8% opening range we can include 66 to AA, AT s+ and AJ os+, (so 8 pairs and 7 high card combos).
In Modern small Stakes by Blackrain he recommends a 6 max MP calling range of 7.5% against an EP raise which includes pairs 22 to JJ, suited KQ KJ AQ AJ and off suited AQ KQ (10 pairs and 6 high card combos). It is assumed we will still be 3 bet by QQ KK AA most of the time.
This widens to a 9% calling range for the button against utg.
Here however with MP in the hand I think most button players will call much wider than that to include all pairs, most suited aces and quite a few suited connectors.
So the flop is 7 4 9 rainbow.. against a typical MP calling range there are only three sets in 16 hands that hit his range so we are up against a set just less that 1in 5 around 20%. Nothing else connects here although he could have an overpair 10s or Js about 12% but we have blockers to these so less than that in reality.
The button has a calling range that may hit this flop a bit better say 9 suited connectors plus the 3 sets but that is still only 12 hands of at least a possible 30 or so hands. Clearly the chances of hitting a set are now less than 10% and the chances of 2 pair are as was pointed out not really even in the button or MP range.
Against those ranges the equity between the all three hands is close all between 30-35%
Looking at this hand this way IMO the UTG cbet looks fine but once MP calls I think he tends more towards sets and/or the overpair, I can’t really see what else he can call with here with and he has to consider the button still to play. Having the button still in helps us here I think.
If MP has 88 1010 JJ he could consider a raise, all of the of the UTG high card combo’s in his normal opening range is missing this flop however, having the button behind complicates things for MP.
No surprise the button calls he can stay in with any pair gutshot combo.
The K hearts arrives on the turn, this gives UTG 5% more equity, see equity calc, it can’t help MP or the button much with their calling ranges. It hits the perceived range of UTG and is a strong scare card.
So do we double barrel on this board… IMO the answer has to be yes we have the initiative and fold equity… if it was a low card and didn’t give us any extra equity then I would reconsider.
If anyone has a set at this point we are now going to find out. MP likely folds 10s and may fold JJ, if the turn cbet is properly priced hopefully the button should let go of low pair/gutshot combos.