Regardless, HOW anyone goes about this is going to be DIFFICULT to say the least to make any edit so the OT payoffs are still a surprise.
The only way I know to do this is change the episode numbers. Make the prequels numbered after the OT.... Then just use voice overs from Obi-wan from OT to intro the prequels... If you do that with all the other changes you would like to make then you don't have to conceal Anakin's identity.