Late to the party, but I have a huge amount of practice playing in just this type of game. So . . . . .
Straddling short stacked is a bad idea. A really, really bad idea. If you want to gamble, go play a table game with a < 2% house edge. I'd be shocked if that $6 is worth $3 and hero doesn't have enough implied odds out of position, short stacked vs a table filled with fifth graders to make up the difference. Far better to fold UTG blind and take a walk.
Hero's rep is likely not tight. Tight players don't straddle like this. And the times they do straddle, there is meta game reason to do it. Often to try and disguise their true playing style vs a table of ever changing casino players.
As for the hand.
Preflop: Hero gets lucky and finds a top 2% hand playing 18 straddle/blinds. The pot is $22 when the action gets to Hero - two $6 limps plus $4 in dead blinds plus Hero's 6 straddle. Jamming $102 into $22 seems wrong unless hero has reason to think someone will call. I think I would size this so hero has a pot sized flop jam with one caller - $102 - x = 2x + $22 Solve for x and get $26.67. So I propose a preflop raise to $25 on top or $31 all-day.
As played, Hero gets two callers - fine. I am proposing jamming any flop without an ace. The pot is $72, Hero has $87 remaining. Turns out Hero flops top set. Excellent, jam. Hero already looks wild and reckless. No reason to think he doesn't jam with J9s or any other hand. No fancy plays, no tricks. Let's play for <tiny> stacks.
We need to be clear that a lot of poker logic is pointless in this type of situation. The origins of this hard are nothing like ABC poker. The villains may well continue with all sorts of silly stuff. This hand is an opportunity to gamble. I suggest hero accommodate this sort of urge.
Hero might still lose as the cards lay. I expect he might - the open ended draw is getting almost reasonable odds if Hero shoves. Even better odds if villain feels he wins if he spikes a pair on the turn/river.
As played the hand replete with misguided fancy plays and mistakes from villains & Hero alike. Ultra short handed poker is smash mouth poker - bet/raise or fold. Hero folds or goes to war. Tricky trappy has a place in deep stacked games with sophisticated villains. Not here.
DrStrange
PS a $1/$3 with a $100 buy-in is a GREAT game if there is no rake. Most players make terrible preflop mistakes. Hero playing a proper short stack strategy is going to harvest a ton of expected value, feasting off all those preflop mistakes. There is a lot of variance, but the game is going to be super easy. Two decisions every hand, most of which will be automatic. Hero should fold a lot. The rake is like a turd in the punch bowl - it spoils the party - because a ~$6/hand rake is death to Hero's win rate.