I will say on the topic of ownership since this was mentioned once or twice between our internal discussion as well, here is my current perspective:
if a player is blowing up a gang shed, it is very likely they are certain as they would not want to waste the explosives. For the player killing them, that would be easily verifiable to them because they would have keys and see it on the map. If the player who blew it up and was killed had suspicions that the player was not in possesion of keys to that shed, they could submit a report at their own prerogative where we would be able to pull that data and determine the outcome from there.
I don't think the ownership thing is an issue although (super hot take) I've never been opposed to allowing civs to check the ownership of a house. If cops can do it, I don't see any reason why civs should be limited in this capacity. Should they be able to walk up and check the owner of every house and write it down? No, because cops generally have not done that. With a really large cooldown timer or something though I don't think this would be a bad addition. Also not sure it is entirely necessary but don't think it could really hurt as far as things go.