Although she does have a resemblance to Satori, said name doesn't seem to appear on the PIXIV tags, and instead appears to be tagged as "Original". Can someone verify this?

I think you're right. Retagging...

Is it really naked shirt if there are panties?
EDIT:

Somewhat similar to naked apron, this refers to a character wearing a shirt without any other forms of attire, including lingerie. Typically, though not always, an open shirt.

Tag should be removed, I think.

She's a character in the author's Nico Seiga manga, My Phone.