I think you line is fine up until river. Probably best to just check and take the show down on river. Ax doesn't fold here and it is like impossible to get value from worse.

This low PPs is fine to blast of sometimes EP vs bb. Especially on a Broadway river i would always bluff this combo, wich is a spot most ppl struggle to find bluffs.

Im not sure if this get to bluff. Probably a mix. You showdown for a little pottshare, beating a few 3xhh combos so probably mostly check. And bluff go for big bluffs with some Jx/5x sometimes. Blocking 2pairs is essential when you start polarizing to 2p+

If you are going to 2nd barrel you want to either a) have a decent number of outs to beat the hands Villain is likely to call with so the fold equity to be profitable is reduced or b) a turn card that will make a Villain that called with a decent hand like top pair start thinking that you have likely pulled ahead of them. Your hand has only two outs to pull ahead of anything that beats it on this turn and that jack on the turn doesn't really give someone with an ace a reason to start worrying here.

I admit I miscounted the outs but I don't know if 12% equity against any made hand aside from 2x helps us much.

"What would be a scare card for you on this board ?"

Truthfully, not much. If this was a 953 flop and I didn't have a pair that fact would possibly be enough for me to not even c-bet since I would have so few options on the turn. Here you are least have SDV and the bet makes since to fold some of Villain's combos that have two overs to your 4s but have completely missed the flop so a bet makes sense. Now let's say the flop had two clubs and the turn was jack of clubs. That would be a scare card to bet. A flop where there are few ways for the turn to help us and few ways for it to look bad for top pair are reasons to consider not c-betting.

"I have AA,AK and more JJ than Vilain OTR so i have to find some bluff to équlibrate my betting range, what hand do you recommande ?"

Once again, with this kind of flop it's rough since there aren't a lot of turns that would make Ax think they are worse vs. the range I raise UTG. If I had to pick it would be when hands like KhQh, QhTh, KhTh pick up the FD (especially with Kh since I now have the NFD) and gutshot, plus some outs to pull ahead of hands like 65, 54 that called with a weak pair+draw. I don't know off the top of my head how much we need to bluff here to be optimal.