i don't think you can waive the deposit fee... if you have a special circimstance in which you can't pay, you may need to talk to the housing office... they might be able to work something out for you but, in any case, i've never heard of anyone waiving the deposit...
The community bathrooms are not a problem at all. Like MrSpam said, there's usually many shower and toilet stalls and not everyone's going to be in the restrooms at the same time. My first year I lived in Rieber hall and as far as I can remember, I never once waited for a shower, sink or toilet. Which you may think is surprising since you're sharing with probably more than 35 other people.
There are overhead lights in each room however, they aren't amazing. I would definitely recommend bringing a desk lamp - especially if you plan on doing any late night studying with possibly sleeping roommates. Each desk has a very uncomfortable wooden chair. I personally didn't bring my own chair - I just stuck a cushion on the wooden one. But, many people do bring their own comfy office chairs.
Just throw your own chair out into the hallway. You should be able to fit a nice little one in there. Something like this (Contemporary Drafting Stools w FlexBack and Footring) would be perfect. Apparently they're called task chairs. This, however, is total redonk. Plus, you'd never get anything done in one of those.