Welcome to YT
Yep girls do bleed when they have a heat....I can't give you any help with how much or how long for because I had mine spayed at 6 months before she had her first one...but I don't think it's very much.
You must be so excited about getting a new puppy!
It is generally recommended that yorkies and other small breeds don't leave mum until 12 weeks, especially the really small ones. I've read that there are lots of important socialisation skills that they learn from mum at around 8 weeks old...so maybe the breeder will agree to keep you pup for a little longer?
Again, welcome and congrats on your new arrival....be sure to post pics when you have her home
xxx xxx