Our scenarios are very similar and I have had yorkies for the last 9 years. No problems here. My yorkie does fine when I am not at home. In the beginning I used a webcam to sort of keep an eye on her. A webcam help a lot for those days I had to go into the office. I wanted to make sure she didn't have separation anxiety and that she wasn't getting into any mischief.
I've also adopted my yorkies. The first one was 7 yrs old who passed away at 13 (RIP Brandi) and the second one was 2.5 years old (I still have her......the devil in disguise
). If you are looking for an older yorkie try pet finder.
The only issues I had with her is the potty training but it was mostly my fault I wasn't being consistent. But once she was fully potty trained, she had run of the house.