What else is there to analyze besides the obvious King Pair/KQ, flush, straight draws?

If river action goes check/bet/allin/call. The winning hand will be a full house more than 50% of the time. Where are you getting 1% at?

FH is possible but pretty unlikely in this spot.

KK/QQ 3b a large frequency preflop (why price in 2 blinds and the EP limper and go 5 ways to a flop?)

KK/33 has to raise my flop c-bet with a decent frequency since we are 4 handed. HU maybe trap a street but not 4 handed

43 folds a lot preflop, has only 2 suited combos left, I think also has to raise flop on this board a lot.

QQ that peeled flop is I think the most likely FH, but don't think even that is super likely give pre-flop action/position.

Of course if river goes x/bet/jam/call he is going to be extremely boat heavy. That's irrelevant to the point I was making.

The <1% is in regards to preflop/flop permutations - ie: of all the hands villain plays that take a flat pre/flat flop line, an inconsequentially small number of them are KK/QQ/44/33 that it has no bearing on how we play our hand.

I'm not going to MUBs a potential river bluff because there is a chance approximating the likelihood of two electrons colliding that villain is going to have KK here. A river x/jam only has to fold better hands 31% of the time to be profitable (415/1340 =31%). Villain is going to have a lot of weak flushes here that can't call off our jam.