Welcome to the club!
Yeah it stinks when previous owners rigged stuff to work and "forget" to say anything about it when they're offloading it onto someone else. That's a definite sign to check for other maintenance issues that might have been skipped over or rigged up.
Overall the Xterras are great vehicles and will put up with a lot of abuse. Though if it has it'll probably just take a little bit of time to get it caught up on everything it needs so it will be sure to stay reliable for a long time to come.
The sensors are a pain when they go but fortunately aren't too bad to wire in. The evap leak is going to be worse to pin down, hopefully it's not making pumping fuel a big issue yet.
Definitely have the timing belt checked. That's the big expensive fix that V6 Xterras need as they pass the 100k mark.
I'm sure once it's caught up it'll be a great vehicle for you. Take care, and have fun!