Hi i was in this situation before. I started naruto online on Kongregate and a few months ago moved to the official site.

I know it is possible to bind your naruto online progress on Kongregate to a oasis account. I think i did it by creating a oasis account using the same email that i used for Kongregate and finding the same server or whatever. You are probably confused rn cause I don't remember too clearly how i did it but i can assure you that its possible for you friends to bind there Kongregate account to a oasis account.