RobinJFisher
I think you'd be crazy not to mention a forearm tattoo if they specifically mention them in the FAQs. All you can do is be up front about it and if they think there's a way around it then great. Really not sure you could get through an entire career in long sleeves, but all you can do is ask.
With regard to accommodation, best thing would be to call the FTOs directly and you'll have a pretty quick answer.
I know with FTE you're not allowed guests staying in your room on campus, but don't know about the prospect of living off campus.