Well about number 2 I can help you. I live in Toronto which is I think we can aggree a tad north of you. I've been walking Sheila (ok carrying, not walking) her 80 minutes a day to and from daycare (right by work) snow or shine. She wears a puppy coat and a small baby blanket now and at first I wrapped her in a blanket. She is smalish and maybe 2 pounds now at 13 weeks. I aked my vet about the cold and mind you he is in his 60's and loves yorkies about my baby and the cold. His response? "for christ sake the breed comes from Northen England, they can handle a little cold"
I do wrap her up if it's below `10 celcius just to be safe though.
My vets opinion and much of what I've read/heard is that what we all have and love ARE little terriers. It's important they are allowed to be just that and not over pampered. A yorkie in their own mind is a big dog, yes protect them but please don't treat them like they are porceline figurines! A lot of breeders feel it's hurting the standard. That's why in some shows the "stand off" where they put 2 yorkies together face to face is so important. Yorkies are a toy dog in our eyes, not theirs
Sorry, if I rambled... I do that! Congrats on your new boy! Before anyone else says it... we want pictures!