Hi and welcome to Yorkie Talk!
As far as the older dog being able to bond - ABSOLUTELY! We got Sandy last year, her estimated age was around 6-7 years old. You would now NEVER know she hasn't been my dog her entire life. She follows me around, wants constant attention, I'm her person
Good luck with your newest addition. I'm sure some of our other members will have imput for you on your other questions as well!