The zipper is along the shoulders, so no, it wouldn't be ideal for full on solo...you need someone to zip you up.
The suit is a double layer suit, which makes it quite rugged. The actual material that keeps you dry is a laminate (rubber like), then you have an outer layer to protect against abrasion. I'm only selling it because I've been issues a new suit for work, so I don't need my personal suit anymore!
I don't have any undergarments but any thermal underwear will work quite well, or you can always find one online for cheap. I do also have some Dive Rite Gators (keeps the air out of your feet if you have issues with this) for sale, brand new, and a nice 5mm Mares drysuit hood for sale.