Hi and welcome!
Thanks for putting much consideration into what you're about to embark upon - that right there is the first right step...so you're already on the right track.
Answers:
1. at least for the first 2-3 wks, a little yorkie puppy needs to eat at least every 4 hours until more mature and stable. But there are options here...you could hire a sitter to come and check on and feed your pup at first, and help w/ potties. Check out Rover.com for sitters/walkers right in your immediate area (I'm a Rover sitter and I think it's an awesome service!).
2. Hard to say "how often". Other places to check are your local shelters, rescues, and/or specific yorkie rescues.
3. Many people do work during the day and also have dogs. They find ways to make it work.