This is Disney we talk about so getting sued is probably expected, they will explain in court how your character ripped of theirs, you defend. Court decides.

If you can point to a non Disney older source where these same details are present you have a likely win.

If there is a Christopher Robbins in the original you can use the name but if there is not it then having roughly the same letters or sound will likely be a loss.

Of course this more assumed law theory of not a layer. Some rich dudes can just trademark the name of fruit, a basic word or even a single letter and we just let them.