I strafed a couple of parked 109s yesterday and after they took enough damage to remove a wing and gear they hovered in mid air like the gear was still there. not sure if that can be fixed but just an observation.
I too have had this happen both single player and multiplayer and others on same server as i was had this happen, sometimes i was in the middle of start sequences others i had not touched anything yet so I'm not sure what triggers it.
Custom skins in MP is possible, everyone who you want to see it has to install the skin into their own files to see your skin otherwise you see your skin and they see default.