I was doing some back-research on Idea Factory titles (mostly adventure titles).

http://www.team-e.co.jp/lovesolfege/index.html

http://www.otomate.jp/will/song.html

I don't have good Japanese skillz. So my question is, what's the deal here?

I ASSUME the deal is like so...

"love solfege" performs the opening theme song for Will O Wisp. Also, if you like her voice, her FULL album has been released by Team Entertainment. But the only thing relevant to Will O Wisp is the opening song.

Anyone able to help?

love solfege is a group of three people: one composer (Shinichiro Matsumoto) and two lyricists/vocalists (Anmi Mizuki and Ayu). This album is their debut, and the Will O' Wisp opening theme, track 9, is on it. As far as I can tell, the rest of the album is original crud.

Full credits on that OP theme are:
Composition & Arrangement: Shinichiro Matsumoto
Vocals: Anmi Mizuki
Lyrics: Ayu

thanks!