Why would that be problematic? If you are going to stand by your assertion that the Moriondor are still Elves and not Orcs, and that the label of Orc would only be applicable to their descendants, then it would stand to reason that only the original Moriondor Elves would end up in the Halls of Mandos when they die. Orcs wouldnt end up in the Halls because Orcs aren't elves, according to you.