Every collaborative project seems to be looking for dedicated artists and programmers but never things like level designers/creators.
Everyone wants to be a designer. Or at least, to be the idea guy.
It is a job that people outside the industry think they really want.
In the professional world the job title of "game designer" is not an entry level position. It requires several years in the industry in some other role. It also comes with a lot of responsibility, a lot of long hours, and lots of people fighting against your work.
You mention computer science, working as an artist, and working as a designer. The three are different roles.
The role of a designer is to design things. Those who fit the role tend to build paper-based games, follow complex rule sets by hand, and study out why some games are fun and why other games are not. Ultimately those who have the job work with all the other disciplines to come up with an design for what the game components should do, then they spend the rest of the development cycle trying to put people back on the track they envision. They start an avalanche and then do everything in their power to keep the avalanche under control.
The role of a programmer is to write code. Those who fit the role tend to understand computer systems and algorithms, understand what happens inside a computer, and tend to tinker a lot with computers. Some programmers can follow the designer career track, but most programmers understand that they would either be bad at it or wouldn't enjoy design.
The role of an artist is to create art (or models, or sometimes animations). Those who fit the role tend to spend their time drawing and doodling and sketching and studying what looks good and what doesn't. Some artists can follow the designer career track, but most artists understand that they also would either be a bad fit or wouldn't enjoy design.
Now if you enjoy design and you are a programmer, that's wonderful. As a programmer you have a very strong influence on the design. Designers produce the best design they can but most of the implementation details are left up to the programmer. As a programmer who has a mind for design you can strongly influence the games you help create. This in turn makes it easier for you to move into the designer role when the position becomes available and your experience warrants it.
I suggest you read the forum FAQs, and since several are links to Tom Sloper's site ("Sloperama") I suggest you spend some time and read all the articles you find over there.
Reading that material should hopefully lead you to answers to your three questions you asked, about your own project, about art, and about doing something else entirely.