I would want it to be like this:
Tells the story of Barry Allen and how he becomes The Flash.
Characters: Barry Allen, Jay Garrick, Iris West.
In the second movie Wally West comes to live with his aunt and her husband, also shows how Wally becomes Kid Flash and there’s a love triangle between Wally, Jesse and Linda Park.
Characters: Wally West, Jesse Chambers, Linda Park, Libby Lawrence; Johnny Quick, Barry Allen, Iris West.
Flash III is a story about Bart Allen, shows how Bart came to the present.
Characters: Bart Allen, Barry Allen, Iris West, Max Mercury, Jesse Chambers, Wally West, Linda Park.
Cast: Who would play who?
Main Cast (movies 1,2,3)
Supporting Cast (Movies 1,2,3)
No Suggestions ( I don't know)
Anyway... What do you think about this, and what do you want to see in the movie?