Yeah it really depends on the vet. Spays normally stay overnight and neuters can
be sent home the same day, but some vets like to be safe and keep them overnight on fluids and to make sure they recover fully. And yes it is normal for them to wait until the dog is fully vaccinated...has to do more with age...most vets will fix a dog at around 5 months, and by then they have all of their shots.
I am so glad you decided to neuter your little chi!
Neutering can sometimes help in potty training male dogs (but not always) since they wont have such a drive to mark. Plus your little guy wont have to worry about prostate cancer or testicular cancer when he gets older.
As for training, petco offers training for a really good price. Your vet should also have a list of places. I would reccommend sitting in on a class to see if you think the trainer will be good for your chi. If they do not allow this then I wouldnt even consider taking your chi there...a good trainer will let you watch a class.
Best of luck!!! November seems like a long ways away but it will sneak up on you quicker then you want :wink: