Congratulations candidgirl!
I think it is okay if somebody else will pay your fees using their credit card. If you will look closely at the payment form, there is a separate entry for the name of the credit card holder if it is not the applicant himself. Second, regarding the supporting documents, it did not specifically say in the checklist that copies must be notarized, unlike in your application package sent to MPNP. Clear copies will do. Notarized copies, if you already have them, are just as fine. Hope this helps! Good luck!