@DRrDUBB I think a lot of people accidentally leave when they become shadows. Somehow the 'spacebar = go to leave menu and ALSO counts as 'yes' if you hit it again' method of leaving the game got re-implemented in this mode. It was that way once in the past, and then they changed it to the way it is in normal games now. I've nearly left a few times as a shadow just because space = wall climb/jump/staying alive as a shadow. As such in the few seconds after you die before your hands stop hitting keys to try and keep you alive, you accidentally trigger a 'leave game?' and 'yes' response.
To your 4th point, shadow dmg is consistent, for some reason if someone is at a lower health amount the shadows deal less to them. I saw someone post the exact amounts somewhere, and I'm not sure why a nearly dead player should take less damage from a shadow, but there it is.
5th - ABSOLUTELY seconded. The arbitrary respawn jump points for shadows are sometimes just dumb. I'll spawn on the other side of the map from the ring/player who killed me over half the time, and then if I try to drop back to them my drop speed goes to crap so it takes ages.
Unfortunately, this game mode is HEAVILY imbalanced in pathfinder's favor. When the drop ship comes in he can grapple up into it and then shadows really can't get up there to kill him. There was one game where it was next to a wall and I'd climb up a few feet and try and turn/jump but I'd never get it right. I'd either hit a wing and drop too fast or go to high and land on the wing.
https://imgur.com/a/hbeBTC9That pic pretty much says it all about pathfinder and this game mode. The only variable I've seen in the matches I've played are how many pathfinders are the winners.