A – unless you have setup and tested a default profile then copying an existing profile and renaming it always causes problems. This is because while you see user xxx or name yyy, the domain sees SID & GUID & AD UID.
B – You state that when comparing an existing working profile and your two ‘new’ users they are the same (except for the name). They shouldn’t be. At a minimum the path to profile on the server must be different. A roaming profile only works if it is owned by the user trying to use it or the network administrator. I am willing to bet that if you check security – ownership of the new profiles it will still be the old user.
C – In fact I se that you did check the path and it is different for each user, then it has to be permissions – ownership of the profile.
Hope this helps