1. Kassela's starting hand ranks 17.0 ten-handed and 15.0 six-handed. And any hand with a suited Ace and a wheel card has two-way potential, especially heads-up. But I think it may be a mistake to try to compare what pros are doing in a high-stakes, slightly shorthanded, televised game against your (or my) low-stakes, full-ring game. For all we know, Kassela is gambling more than usual precisely because the cameras are on him.
Did you see what he did on Halloween, playing NLHE? Start watching this video at 11:50:
https://www.youtube.com/watch?v=qwtWrH672go. Kassela has reraised preflop with a pair of black jacks, the flop comes Q84 all spades, and he shoves all in for 2.5x pot. Then he shows his opponent the Jack of clubs (huh?). She has KQ of hearts, and it takes her a moment to comprehend that there's no way he can have her beat. Maybe he meant to show her the Jack of spades—maybe he was drunk or got caught up in the silliness of that night; maybe he just doesn't care about money. Maybe we shouldn't put too much stock in what he does on TV, is what I'm trying to say.
2. Correct. They both have a 654xx low. So which number is lower, 21 or 32? 21, obviously. Or looked at another way: they both play the 542 from the board, so which number is lower, 61 or 63? 61, obviously.
3. Correct.
4. He loses to a wheel, doesn't he? If I were in Synder's seat and I had a wheel, I would go for the check-raise here. Maybe Kassela fears the check-raise. Though I'm with you: I would bet this turn from last position with Kassela's hand.
5. No, you're right, and the commentator's wrong. If you watch enough Omaha livestreams, you'll hear mistakes like this a lot. With four cards in multiple players' hands and three or four cards on the board, there's a lot of information for the commentators to perceive and process in real time. Ideally, you'd have two or three commentators who are all experienced enough Omaha players that they can correct mistakes like this very quickly.
But in this case, the correction would be that Synder has 3 outs for a scoop (the 3 remaining Aces), whereas Kassela has, what, 9 clubs plus 2 9's plus one 5 for a scoop (that's 12 cards total)—plus 2 non-club 3's give him both the wheel and a 6-high straight, for three-quarters of the pot. So I'd say Kassela has a partial freeroll here, but it takes a minute to count up their respective outs accurately.
Not only that, but Kassela can't possibly know he has a partial freeroll (unless Snyder accidentally exposes his entire hand). If Snyder has a wheel, Kassela is drawing to get half, or maybe three-quarters, but he gets nothing if he doesn't improve.