Season 5: - "A friend in FBI" phrase of Red John is/might be fully confirmed in 5x05
Season 5: - "Shooked hands" Minelli suits that role for that quote in 5x08 said by Lorelei M.
Season 1: - Can't exactly remember which episode it was, but when the team was chatting with Red John's account via the computer, the eye vision reflected from the computer of the opposite side (which was in that case, Red John) might belong to Minelli himself, as he can easily access the CBI network
Season 1: - Minelli might have resigned in order not to make Jane suspicious about him as a Red John candidate
Season 2: - He keeps in touch with Patrick and helps him illegaly in an investigation, which can be a tactic of the writers to keep Minelli in the frame, as his role was not essential for recurring after his resignment in the end of the first season; by that, we can also say that writers intentionally shoot the episode 5x05 to keep Minelli in the game
Personal reasons: Gregory Itzin, who is a terrific actor, plays for the bad natured character more than usually in series or films, so he has the right aspect and charisma in the words of being the Red John
Personal reasons 2: In these kinds of fiction, the identity of the main antagonists turn to be someone that the audience knew from the very beginning, so Minelli is very appropriate for that role.
Roy Tagliaferro: By the measurements of body and size described by Harker, Minelli
suits to be the alter ego/alias of Red John
*He definitely has no alibis in many of the murders
The writers confirmed the narrowed-down list of Jane's, but that doesn't mean that the list is the absolute correct cage to hold all the candidates within it. Writers have every right to mislead the audience at all times, that's a well known tactic of fictionists.
His motives to be Red John is exclusive yet, that's for sure. But hence, he has many sidekicks and associates to build up such good network.
That's my best guess...
