I liked your post so much, Barry. I'd like to add some things I've picked up here and there if it helps anybody. I've learned there is no one size fits all protocol, and not all vets have enough experience with rescued animals because their client base simply doesn't offer up the experience, and things can take a wrong turn with the best of intentions and professionals sometimes. A really good vet is priceless.
Vaccinating: I found depending on how compromised the horse is, vaccinating may be best withheld if possible until the horse is healthier; deworming protocol same thing, depending upon the exam. It isn't rocket science, but yet it's not a piece of cake either, is it?
I don't know if anyone here is familiar with Bach's Rescue Remedy (some people think it's airy-fairy) but I've used it for traumas, and even some gas and stress colics along with some acupressure work, and it's pulled a lot of them out without the need for banamine. I'd say colic's one of the #1 concerns with the newbie rescue. I'm also a very big fan of microbials, that gut balance is so so critical.