If your Ideal Client Profile dictates a written plan and you charge a fee for it, should you also charge a fee for a plan for current potential Ideal Client's? Should there even be a fee charged for current clients if they come over to the New World?

Yes, if there is a fee you should charge that fee to existing clients as well. Particularly your new Ideal Clients even though they come from existing client base. Some advisors offer their existing clients a preferred price on the first year’s planning fee because they are existing clients.