Against "internet kid" and as played I'm generally calling and happy about it.
You need to call 215 to win 598 so you only need to have the best hand 26.4% of the time. This player archetype can take that line with much less than KhXh or AhXh. With the line played this way, Villain can take this line with any flush, and maybe even some straights. Not to mention this hand was played in a strange way and that could induce all kinds of weird things.
All these things considered, I'm calling without a rock solid read that suggests otherwise.
1+2) Being oop with several players behind you who are likely pretty aggressive, I like checking the turn actually. And the action comes strong and Villain probably has a flush, AhX, a straight, or some combo draw, and possibly even air if that's his MO.
Against that range, I like flatting because he'll probably be the type to barrel again with this whole range on blank rivers. I don't like jamming as much because it allows him to fold his air, straights, small flushes, while calling with KhXh and AhXh and possibly call with AhX anyway since the match is close for him. This allows him to get away from the hands he's crushing you with and calling with the ones that crush you.
So I'd say interesting hand, but NH if he spewed into you. If he did have a one of the two higher flushes, I wouldn't feel too bad. I'd still call and feel good about it.
PM with the hand result if you don't mind