I would say your schedule is reasonable as many people who have yorkies work full time myself included. I also adopted an older yorkie so that may it a little easier as I didn't have to worry about all the things that come with a puppy.
Your setup is actually identical to mine. I worked 40 hours a week but I am allowed to work from home at least one day a week. I walk my little one at least two miles a day (she actually could outwalk me....I'm the one who gets tired
)
I have pets my whole life and they were just fine when being out the house for 8 hours a day. I think it is people who have extremely busy lives where i wouldn't recommend it.
For example my current yorkie came from a household that loved her very much. She was extremely well taken care of but the owner was working fulltime, in school part time and had a 1 yr old child. She would leave for work at 7 in the morning and wouldn't get home until 10 at night. So in the best interest of Duchess, she gave her to me because she knew Duchess needed more attention. She actually changed her mind as she was looking for a way to keep her.
Now Duchess is in a household where she probably get's too much attention. I think she hides from me just so I can't play kissy face with her
