My Violet was just spayed at 5 months. She had to have surgery for another reason, so they did the spay while they were in there. Honestly, it is awful seeing her recover. If I'd had a choice, I would not have spayed her until at least 7 months, especially if your yorkie is tinier.
I opted not to do the microchip because she was going through enough already without adding anything else to the mix. But even if she had been perfectly healthy, I don't think I would have done the microship simply because Violet doesn't really go outside very often (she is pad trained) or for very long. And I just can't imagine any circumstances under which she would "escape."
