I'd say no to everything. Switching Wis for Cha may initially seem 'mostly harmless', but I'd be afraid he'd later pull some crazy stunt utilizing obscure feats or prestige classes.
It's better to say 'no' right from the start. If you start saying 'yes' now, it will be more difficult to say 'no' later when he comes up with further changes that aren't as harmless.
It's better to say 'no' right from the start. If you start saying 'yes' now, it will be more difficult to say 'no' later when he comes up with further changes that aren't as harmless.