I went through a similar question process. Each dealer will charge a different amount to CPO...some will do it for the fixed base price, other will charge the base price + parts/repairs and labor. Thus it will vary, so you have to shop around. If your car is pristine, they should CPO it for the base price.
Regarding negotiating the residual, again it is dependent on if your car is worth more than the residual value and if they are confident they will resell it. If not, you have room for negotiating.