Does Renko hat is enough to tag her?
I know hat is important for touhous, but she is not a hat... Or am i wrong?

Nah, she's not Shinpachi. Don't tag her I say.

I've looked through a few posts just to be sure: post #2111275, post #2518818, post #2633741 (and its children) and post #2524543 are all tagged with their respective character tags despite the girls not being there in person (or not in full view at least).
So yes, the hat is important enough to be tagged.