Yeah. I know what you're saying about the money. We're the same way, we stay at a pretty level amount, where we're fine if there is an emergency but god forbid we actually WANT to buy something. haha.
Where I am, we have low cost spay/neuter for cats and dogs. When I had my outside cats done, it was $75 for her with shots and $65 for him with shots. My dog/cat vet will also spay/neuter "strays" for like $60. Maybe you could look into something like that, like a low cost something. A lot of times places have clinics for the cats/dogs. My mom got her dogs neutered in Tenn. at a clinic and it was MUCH cheaper than the regular vets up there.
I know with most rabbit spays/neuters though, its upwards of $400 per rabbit. I was SO lucky to find my vet at $190 for a spay, because its the cheapest in the area. Sometimes vets let you do payment plans, like if you pay half at the time and then the next half when you can.
Personally what I would do, is get the cat fixed one month. Then wait a month. Then get a rabbit fixed and do it like that. Like, alternate months. So you're still spending money, but its not like you're spending $2000 in one month on animals being fixed. But thats just me and thats the way it would work out with our finances.
Honestly, today, I think you should just leave them alone. You're upset and tired and stressed and its not the right time to mess with them. I mean, clean up where Thump has sprayed, but don't mess with them. I think if it was me, today would be my little break day from messing with them too much or trying to figure out what to do with them.
Sometimes I have to step back and take a breath to clear my head. Then I can usually figure out the problem better.