As a creator with little to no skill at illustration, is the use of public domain, or common license art frowned upon, or if the art is commissioned and credited does the artist need to be a participant in the jam as well?

With the theme chosen there is a lot of good avaible public domain stuff, but it’s going to lack some of the cohesion that a graphic artist is going to be able to bring to the project. Unfortunately I don’t really have anyone I know of that would have the art skills and would want to participate as a duo so commission etc is my primary option.

There's a ton of great public domain work, and it's encouraged for this jam! I'd say if you're commissioning work, be sure you have commercial rights if you're selling it! It's one of those cases where you're best communicating with your artist, or sticking to public domain art with good faith looks at using licensing.
That said, your work doesn't need to have art at all, and a lot of my favorite games are plaintext documents. Art helps communicate vibes, but it's not the only way to do so. I'll try to compile some resources for good public domain options, but submissions aren't graded, so just have fun and make something cool. Nobody will slight you for not being a master graphic designer.