I wouldn't worry about a harness until you are well settled in weeks from now IMO.
Collars are also optional if your cat is going to be indoors. I found that my cats were happier without the collar on, and really only tolerated it because they couldn't get it off so eventually gave up. Fur bunched around the area as well, and no reason they don't have to groom that area any less than the rest of their body. I do keep ID'd collars around for vet visits and the like, but thats just a matter of slapping it on. Make sure its a breakaway and you should be able to slip two fingers under there.

I just bought beds from Petsmart, but really they will sleep anywhere, and its hard to predict what they'll like. My beds went for months without being used, but now they are favorites though after I tweaked the location and they figured out its comfy. Many people find that beds are never used though, so are a risky investment. I have found that my cats prefer to sleep up high, where they feel safe and can let their guard down. One cheap bed I had considered was a corner hammock, where you literally just make a three point connection w/ some cloth on a corner up somewhere they can jump to.