Re: Maybe a stupid question but is there any way to replay specific missions?

nope, only by replaying the game. But you can play MOST boss fights again by using the battlegrid mode in New Journey +  - this excludes these bosses:

I know, that mission is FUN. I look forward to it every time I go through it. Fortunately, it's in the first part of JFO so if you start a new game, you won't have to spend too much time playing to get there.