ZnKmom,
What a great post you've entered !
Your detail on how the Resident animal should be treated, is spot on, and
you're SO right about how the tenured animal, will assist in teaching the
newer one so much.
One further thing I'll say is, that every dog has it's own personality.
When replacing one, try not to think it's taking the other's place, but
allow it to make a place of it's own in your heart.
Yorkies are SO good at that, if given a chance.