You guys really think Dan Houser sat there and said yeah put a pic of a jetpack in the Mural but dont give them one cuz i wanna piss off all my fans .. come on !! thats rediculous
Yea I only tried it once and didn't save it after going back, but I could definitely switch to Michael.
I think the replaying mission thing is purely to get Golds and leaderboard stats.
when accepting to replay a mission it even tells you it is generating a save point.
meaning that any replays take or add nothing except, as you said. Leaderboards and medals.