I guess he'll use evil magic or something, or be so skilled in Ringmaking that Celebrimbor trusts him, I guess. Ar-Pharazon and the King's Men will be Ultra Dark MNGA so they will be dumbies who fall into his trap, who strong black lady Tar-Miriel will oppose in secret as the real leader of the elf-friend (Elendil and Isildur will flee Numenor under her orders and organization) and her sacrifice will save them (I also bet she'll have a romance with Isildur). Galadriel will not be fooled from the start, I guess but the dumb men Gil-Galad, Elrond and Celebrimbor won't listen to her so it won't matter. I bet Prince Durin IV will be stupid enough to accept his ring but black dwarf lady who is his wife(?) will be the real ruler of Khazad-dum so it won't matter. I'm also betting that the meteor the "Harfoots" find will be the material used to make the three elven rings.
Any other predictions?
These all seem very reasonable based on what I've seen so far.