It isn’t canon, but it could easily be made canon. And even though I didn’t really like the idea at first, I now feel like it would be a good way to retroactively shore up Star Trek lore.
I find it hard to believe that there are MULTIPLE demigod-like species in the Milky Way alone. I feel like they would have stepped on each other’s toes until only one prevailed (actual gods like the Prophets wouldn’t care or be affected). Having Trelaine just be an errant baby “Q” who got scolded for consorting with mortals prevents that inevitability.