I think Mal probably does remember the old Leon and he probably understands him fairly well (LOL...not like Jake claims to understand him). Mal knows what it's like to have your private life invaded and people always whispering and asking questions. I think he gives Leon the space he needs.

I think Mal would be amused with Brian, if he knew him. Almost in a paternal way.

Oh yeah, Mal would know of Ginger. LOL! Besides...she's a cheerleader, for cryin out loud!