Knowing the original intentions of the competition would still be nice though. An uncollectible 1-of in an FG deck is supposedly allowed to be much more powerful
Fair enough. I would have liked to avoid giving a strict ruling on this, but oh well. The text of the rules says "Create a unique card for one of the False Gods! One copy of your card is added to the existing FG Deck(for 2 in total)." In normal play, when you beat a FG, you have a chance of spinning any card in the FG's deck as long as it's not an ultra-rare. Therefore, the question becomes whether your unique card is an ultra rare.
This competition was not intended to consider the matter of card rarity, and it's arguable whether rarity is even a matter for card design. Why is arctic octopus a rare, but phoenix isn't? Why is Miracle a rare, but not fractal? Etc. You know that the FG will get one copy of your card and that's it. You also know that a valid submission only requires the upgraded version, and that would not be available in the bazaar. Therefore, the only way to get the card, if obtainable, would be from defeating the FG.
Given that people have already made submissions assuming both that it's a normal card and that it's an ultra-rare, I'll put it this way.
Your cards are not ultra-rare unless you say they are. All ultra-rare and non-ultra-rare cards will still be voted on together. Non-ultra-rare cards probably have a small advantage since being player balanced is never a negative trait, while being player unbalanced could be considered negative by some.