The problem with 0/0 variant is that all of them require an additional ability to keep them alive. That is going to push complexity too much at common IMO. From power standpoint, something like Glazed Screen is an anthem with a body attached so it's absolutely unacceptable at common. Of the cards Pharmalade lists, this Foggy one is the only one I would be moderately content with at common, but even it has the serious issue of granting nonsquared buff. Much of the time, preliminary limited tests are done with commons only so this tribe should be able to function with commons only.

The version with 1/1 has the problem of variety. There's only so many different designs of global enchantments you can make at common that only produce 1/1s. However, this affects gameplay as well. As mentioned, those global p/t buffs are too impactful at lower rarities, so they aren't a solution here either. A single 1/2 or such is going to make attacking so unprofitable with bunch of 1/1s that you would have to get 4+ of them unblocked for an attack against such a board for it to be worth it - not to mention if there are multiple bigger creatures waiting. I would wager that would lead easily to stalls and painstaking chumb blocking.

On the other hand, with the variable p/t version we have at the very base level all the french vanilla variants from Shimmer 1... to 4+ available for common, without even exploring the mechanic any further. The core concept of enchantment based creatures remains intact either way. As such, turning the mechanic into an action ability (or whatever) is counterproductive since the essential designs are those french vanilla creatures, where as those novelty designs where an action keyword might make more sense (such as Shattered Dreams) probably won't even make the cut in the end. Similarly, IMO turning the certain cards into sorceries, instants, or creatures where applicable would undermine the fundamental theme, which is the separation of essence/soul and body/corporeal manifestation, which applies mechanically as well as in flavor. Cards like Regress and Perilous Research will now play wildly differently compared to having Glory Seeker vs having a Unshattered Shard. While one might see having a vanilla enchantment plus a separate body as a "gimmick" of sorts, I would see it as a clear mechanical motif that contextualizes the cards clearly. They connect this "tribe" in a novel way that makes all cards that care about enchantments and/or additional permanents in general (and tokens as well) a boon and a synergy that you don't have to state out loud.

Hopefully the train of thought is understandable here.