Mentioned, but not claimed.
Roland William Saint-Clair mentions several Alexanders in his "Saint-Clairs of the Isles" as children of certain lines. Yet he has no further mention of them. He doesn't even bother to explain why he makes no further mention of them. Perhaps it's because they went to America. Perhaps they died (though he often noted that).
Here I'll list those that I've found in his books, the Alexander's without a home. In hopes that they might provide a clue for us later on.