7BLS is perfect size for a yorkie
I understand that this may be too difficult for you . Did you want to have your dog use as a service animal? I think you could train your yorkie just the way you want to,and he will be the perfect dog for you .
Yorkie's are hard to predict what size they will be when fully grown. I think they are perfect size at 7LBS , and still tiny dogs .
If you need to rehome let me know , I love to have him . My Suzi is about 7LBS , and I am disabled . She works perfect for my needs , she is a service animal too. I also have a shih tzu who is a butterball , but she is mostly all hair.
I hope you can keep your new boy , he sounds precious.
BTW , Suzi loves to run around and does not like to be carried around much . It is easier for me NOT tohave to carry her, due to my condition .
You could by a special carrier for him , and allow him to wear a harness . He is safer this way to ,mobility wise .