Wooden indoor housing/second bunny sex?

Hey guys !! Sorry if this is against the rules but I'm gonna ask a question about two different topics!

After a near incident with a neighbour hood cat and my rabbit I've decided to bring him inside either till I can get him a more secure hutch or just keep him in permanently im not sure what would be best for him yet !

Anyway I want to get a rabbit pen from boyles (http://www.boylespethousing.co.uk/rabbit-housing/2x1x1m-rabbit-pen.html) the only thing I'm worried about is him accidently weeing on the wood and it smelling if I can't get it out of the wood so if I was to put an aquiarium sealant on the corners and sides of it or a pet safe varnish, would it make the pen water proof??

Also, I'm getting a friend for my bun, he's a 3 year old male so would it be best to get a rabbit at the same age as him from a rescue or could I get a younger one? And what sex would the rabbit need to be? I'd love to get another male but I don't mind getting a female. Do male parings work or not or would it be really hard to bond them? I ask because there's not many rabbits in shelters near me and the RSPCA branch near me have stopped taking in rabbits, sadly! And the shelters with rabbits in either have only males or really young females !!

Hello [emoji4]
Lots of people use Lino in the floor, with wooden battens around the edge to stop it being chewed?
And from my experience a neutered male female pair is easiest to bond (other pairs aren't impossible but my boys fell out and now both have wifebuns).
Hope this helps!