Can you move a litterbox behind the recliner, or just put an extra litterbox there?

I know these are not your kitties, but having the extra box might help.  Try cleaning the soiled area with vinegar (sometimes the smell of vinegar turns the cats off, as well as cleaning), cover with a box or somesuch until it dries, and then put something under the new litter box (plastic? newspaper?) to catch kicked out litter, and put the box down.

Once cats have indiscriminately defecated/urinated somewhere other than their litterbox, they have a tendency to keep going there if they can smell it.  It is difficult to get the scent out so they can't smell it.

Your room-mates are really irresponsible, but that is not your fault.  You should not be responsible for the neutering.  If you neuter them, then they should become YOUR kitties.  After all, if they are too cheap, they don't deserve them.  This would be your decision, but I am not going to suggest it, as someone else did.  It is an expensive one, and they are not your cats.

I had my sister's male cat neutered and put on my veterinary charge account, and my account allowed me to.  She was in a bad situation, and he needed to be done right away by my estimation.  I did not want to see the female get pregnant, and then there would be more babies in the world to try to find good homes for. However, my situation is completely different from yours.  Why won't your room-mates get the cats neutered?  what on earth is wrong with their brains?  

You may wish to check your area for local programs, perhaps there is one that will neuter the cats for a minimal fee? I would drag the room-mates back into a discussion, try to eke some cash out of them, once you find out what the cost might be, if you decide to go this route.

Good luck!

Mel