looneytunes,
These monthly projects are simply a way to expand on and challenge everyone's current lead guitar techniques by applying them to instrumental backing tracks (that are provided in the 1st post of the thread, and everyone's submissions are subsequently added on top)...hence the thread title, Monthly Solo Assignment. Vocals are not the focus here. Some members do often post their own song compositions (vocals included) in other threads in the Listening Post, but that's not the focus in this thread. Rather, it's applying some of what we're conceivably learning in the lessons regarding...playing guitar.
I suspect some of your confusion (above) arose by mistaking Jeffhx's link to his music page as his own contribution in this solo assignment...it's not. That's just his signature that is posted with every reply in every thread here at GT...some use famous quotes (like mine), humorous one-liners, or links to various pages of their own personal interest.

Superhuman,
Great bt submission. You've always been one of my favorite players around here. For no good reason I've never consistently participated in these challenges (and I haven't been around GT at all lately), but I think this one will get me off my ass and make an attempt. I'm no shredder for sure, so I don't know how I'll approach it yet, but it sounds fun. So far, I too have refrained from listening to anyone's submissions for the same reason, but look forward to them.