Since Yasu and Ushiromiya Lion are the same character just using a different name I see no point in creating the Yasu tag, its like doing so for Shannon's and Kanon's real names.
So creating the tag will maybe just create confusion among some users confusion overall be a waste of time.
Given the fact that we don't even know what Yasu even looks like, she doesn't need a tag. In this picture, it looks like Ushiromiya Lion, so it warrants that tag.
A Yasu tag can be created in the future when her true appearance is revealed.
