Any indeterminate token creators don't count for uniqueness.
If you can search existing cards for the string "[p/t] [color] [type] token" and find any results, it's not unique. Otherwise, you're good.
Adding legendary and a name or some other supertype/characteristic is fine as well - "a legendary 1/1 red Goblin creature token named Young Squee" is unique by my standards.
I think designing a non-Aura enchantment as a common may be a mistake… unless you are actually a genius and are simply trying to weed out those who fail to understand why non-Aura enchantments aren’t at common and are in fact looking for enchantment cards of multiple types.
Also, if you get no takers, I could totally host a CCL again.
Actually, this game has plenty of common enchantments that aren't auras/creatures. From recent history, I remember the cycle of fonts from Theros, oblivion ring-effects from various sets, expeditions from Zendikar, Seals...
They had a cycle from SOI, which were sac effects designed to help with delirium.
Theros had some, obviously, the non-creature ones also being sac triggers. But these were mostly here because Theros had an enchantment theme and helped with stuff like constellation.
BFZ had one which was a little odd; I think it was there to help with creature removal as — surprise! — BFZ was creature heavy.
Anyway, I think my point is: common non-Aura enchantments typically don’t exist because unlike creature removal, enchantment removal is not in all five colors. They can exist for the right reasons, but knowing the type of set they are being designed for is necessary to determine the reasoning behind the design decision for the card.