Ceiling height is a big issue if you are doing large format. If they are 8 feet you are fine at just about any height you put your counter(s). If you are in say a shorter basement look for between the rafters to raise the head of your enlarger to.
Wet and Dry sides is how mine was, at school wet was the middle with enlargers and a changing room around the outside. Don't cross the streams (wet or dry).
I've never seen a darkroom with white walls, mine were mat brown (unpainted dull side of press board) at home and black mat paint. White reflects light and might lower the contrast of your prints. Might not depending how much space you have, but I'd go a dark mat color.
Depending upon how much printing you want to do, make the height of your printing cabinet/table comfortable for you to lean over a long time.
I had three safelights in my home set up. One over the developer try, and two in the dry area.
B2 (;->