Re: My cats are urinating on blankets, furniture in their room
Hi, well ... I don't think spay/neuter has anything to do with territorial issues and it seems like the cats are okay with the dogs? Not running/hiding and spending time near and around them...? My 1st suggestion was going to be vet visit to rule out any health problems related to UTIs, but you're already doing that. Afterwards, if it is behavioral, I don't have much experience with that area and hopefully someone else will chime in.
You can clean their previously-pee'd on areas with enzymatic cleaners. I like: Nature's Miracle, OdoBan and Simple Solution. Really soak it on and allow the enzymes time to break down the odor-causing organic material.
Best of luck,