Take a moment and just try to picture that. Try to imagine Sean Connery singing "Edelweiss" in his brogue. Does. Not. Compute.
Granted, it's difficult to imagine anyone but James Dean playing the lead in Rebel Without A Cause, but it seems particularly difficult to imagine Tab Hunter in the role. Hunter had the looks of a movie star, but none of the dangerous edge that Dean brought to the role.
Kim Basinger is a fine actress in the right role, but she would've been all wrong for the role of Clarice. Jodie Foster brought exactly the right mixture of vulnerability and toughness to Clarice and she more than held her own against Anthony Hopkins in his signature role as Hannibal Lecter.
I'm hard pressed to imagine how this would ever work. I... yeah, no.
Again, I don't know how this would've worked. Robert De Niro's performance as Travis Bickle is so defining that it seems in hindsight that no one else could have played the role.