Sorry I'm not too much help here. I remember a discussion a while ago about the amount the neighbor received when you tapped on something. I think they were discussing whether or not there was a multiplier for clearing something a neighbor tapped, but sorry, I don't actually know what the end result of the discussion was...
Also about the righteousness, i ran a search and found the same stuff I think you did....I could be wrong about that too but that was how I understood it. I honestly never really payed all that much attention to the stars so I was just quoting what I understood it to be. I really have just pretty much figured that if they vandalized you they were ok with it and otherwise I just don't do it myself.
Maybe someone who might know for sure might be more helpful about the vandalism/riteousness stuff. Maybe Nintendo may know...he seems to know a ton about the workings of the game.
On a side note, that's cool about the stealing a lemon tree...didn't know that was ever a thing in the game. :)