Seems pretty fine to me. I'd just like to add two more options for discussion.

Option 1: Raising the turn: We could raise the turn in hopes of getting value from an overpair containing a heart, a hand like AJ-KJ (with a heart) or QJ, hands that they would follow this line with. The thing is that, since we called the bet on the flop, we probably have something. Combine that with a raise on the turn and our range seems pretty strong (two pairs, trips and flushes).

Option 2: Shoving the river: Could they call with a hand like an overpair thinking that we are bluffing with a busted draw?

I think preflop is probably a fold vs UTG open, post flop is fine. Guess we could raise the turn for the reasons stated above but overall I like your line. Don't see any reason to shove the river as I don't think a worse hand calls.

Preflop is probably a fold, indeed, but calling is not out of the question. If we expand our opponent's range even further and include any A3 or even K3s, then more hands that we beat are in their range. But, at the same time, we'll have to add to their range any Ax and Kx of hearts. The thing is that, at first, I assigned a range to them that now I think was too tight (as it seemed from my first post and as it turned out in the hand). In this hand, we either have a flush or nothing. Maybe A3s that we called preflop with, but those are only 2 combinations. How possible is that he calls our river shove with A3, K3 or an overpair against what seems to be a flush? I don't know. But he definitely calls with any better flush and a full house. That said, I think shoving the river gets out of play, as you said. Calling the turn also seems better than raising for the same reason (except that he may continue with the nut or the second nut flush draw). It turns out that he ended up hitting a weird straight with which he decided to bet for value(?). But math says this was and will be an exception.

Curious for you guys to elaborate on why preflop is a fold?

I'd say this kind of hand has pretty good playability and I'd only really play it on the BTN. Perhaps the CO in some spots with reads etc. I think I'd stop at 65s for my calling range OTB.

In my opinion, calling is an option but you'd first have to consider who the UTG player is, how the blinds are likely to act and, of course, your postflop skills. In general, I'd argue about the playability of the hand. Not only it's in the bottom of your range, it's a dangerous hand postflop as it's a great example of reverse implied odds. It could cost you a lot of money if you got too fancy about a made flush or a straight, as your opponents could easily have a better one. This particular hand is a great example. Notice how many better flush (A-high or K-high) combinations and full houses are in your opponent's range. It's a total of 20 combinations (19+1 if you add 33 for quads). When, at the same time, you only beat an overplayed overpair (12 combinations), any overplayed A3 and K3s (10 combinations) or a busted flush draw with an A or a K (less possible that he bets the river with these hands). Mathematically, calling the river is the right play. But this happens only because, in the micros, anything happens. This hand is most of the times a loser against stronger competition. Add to those times when you get 3-bet from the blinds and probably have to fold or when you end up chasing a draw with or without a pair. I would say that above average postflop skills are required in order to play this hand profitably. That's why if I'm about to play it, I'm more inclined to play it from the blinds where I'm getting better odds and closing the action. But, all in all, playing it is on the looser side.

What would you suggest is a good calling range In LP?

Agree with calling hands like this is not good. I would 3bet or fold.

Typical answer in poker: it depends. Depends on who the original raiser is, who the players behind you are, your image at the table, any history you have, your skill level compared to your opponents, how you feel at the moment, how much tolerance you have to variance, reading abilities, your feel for the game... Anything that affects any hand. And that's something that will change from time to time and you'd probably have to figure out on your own through experimentation and feedback. Phil Ivey could probably pick any two cards and outplay us whenever he got bored. But we don't have neither the level nor the experience of Phil Ivey, so we have to find our own confort zone and build from that.

So what kinds of hands would you flat vs an unknown?

Many of the above variables are different simply because we're not the same person, which in turn means that the answer to that question is not the same and may differ a lot. You might be 10 times better overall poker player than me, so you want to flat with a lot more hands, simply because you increase the number of hands you play and the number of +EV bets you make. So... Why does it matter what hands would I myself flat with?

Was just curious, maybe you have some good thoughts that might help me think differently

Not averse to flatting suited connectors on the button providing the blinds aren't squeeze happy - helps that you are sitting 120bbs deep with villain also.

I think if we say "raise river" we would just be results oriented. It's a paired board and you have one of the smaller flushes out there so I wouldn't be doing any raising on the river. I think as played this is fine.

Versus an unknown I think the flat is fine and would play the same way postflop.

Nh imo.