I don't think there's enough information here to theorize. We don't know if the shot was from a great distance or just a few feet. We don't know the position of TB when he was shot, whether he was laying down or had sat up in the tent and turned a light on because he heard noises outside (the light and sitting up or crouching within the tent would provide a silhouette and explain a torso shot).
If there were sounds outside, then did the BIL in the other tent hear anything? A confrontation at that time of morning outside the tent would suggest a greater chance of the BIL being woken up. If there were softer sounds that woke TB and TB didn't exit the tent (and have an argument with someone outside) then the BIL is more likely to sleep through the incident prior to the sound of the shot).
Suicide or an accident with a gun belonging to TB would suggest that the gun would still be in the tent, and that there would be no outer entry hole in the tent. We don't know if there's an entry hole in the tent or not. We don't know if the gun has been found, but if it had been found in the park and could be connected to someone who had a known connection to TB or his family that should point them to a suspect, yet an earlier post said that LE had stated they had no suspects...which seems to point away from anyone in that related group who were camping together.
The reports of other shots in the park over the past 2 years, they seem mostly to be cars being shot at (with the exception of the birdshot incident). I would wonder if there was a single person shooting at cars for fun and if they'd escalated to taking a pot shot at a silhouette in a tent?
TB's wife appears to have kept her maiden name as her surname, possibly causing confusion to reporters over whether or not they were married or divorced. <modsnip> The place, time, circumstances don't really suggest a 'hit' to me with a cause outside of the park.
The Blaze Bernstein connection sounds interesting and I'd want to know more about the circumstances of his death (I didn't follow that case). But if the synagogue has a congregation in the thousands then it's more likely to be a tragic coincidence.