Project Hoyocosmさんのイラストまとめ

Otto and Ayato are the only variants so far that are color inversions of each other.

Whether or not this poses any narrative significance can't be said as of now, but it's interesting nonetheless.

Variants don't have to be 1 to 1 with each other.

For example, Su says in Elysian Realm chapter 3 that he saw a female variant of himself.

For another, incase anyone thinks Kusanali can't be a Theresa variant due to dissimilar names, she also has a variant named Zhuge Kongming.