#1. I have my own feelings about dogs feeling spite towards humans, I disagree but will keep that to myself
, Maybe try running him out, or put him on the pad B4 you head up the stairs so when you do his bladder is empty?
Treats, Yorkies are a true terrier by nature and love to bury their treats, this is what many dogs/wolves do in the wild. Mine will chew their bones for awhile and then go bury them outside or in my chair cushion or under their bed, its just what they do.
Not much help for you, but there you have it!
Kathy