Oh,c'mon! Yes,you could get any talented actress to play MayElla. And I suppose that there are kids who could play Scout and Jem. But how could you possibly recast Atticus,Tom Robinson or Sheriff Tate? For that matter,Cal...she was excellent too. But the questioning of Tom Robinson by Atticus,and his summation,are set in stone.
I’ve already posited Ian McShane for Atticus. Michael Clarke Duncan could have done Tom Robinson very well, sadly he’s gone. There are great actors out there.