This would be my version.
There would be a flash back scene where Micheal along with his young family make a deal with Dave Norton to have Trevor killed and Brad locked up, then we start Prologue, After the bank heist in North Yankton, Micheal's plan fails after he gets shot in the chest but survives (but plays dead to fool the other two), Brad gets shot, also survives and Trevor escapes alive.
Brad ends up getting arrested and believes Micheal is dead, Micheal then flees to Las Venturas with his family, while Trevor escapes elsewhere before finally heading to Los Santos. Trevor then robs some place then kidnaps Wade, killing his family (expect for Floyd) and keeping him as an hostage.
Meanwhile in a huge mansion in LV, Micheal is having problems with his family, and contacts Lester. Lester manages to tempt Micheal into returning to crime. After a few jobs, Lester requests Micheal to meet a new contact who is in training - Franklin in Los Santos. But after a while Trevor catches Micheal around and threatens to kill him.
Soon After, Trevor sets up an heist to break out Brad from jail in North Yankton. This succeeds, and Trevor tells Brad what happened. Brad then sets up a safe house in San Fierro.