Agony - Chihuahua
Agony actually gets compared to a dog a lot. I think of her as a formerly caged Chihuahua that's seen some stuff. Like the Chihuahua she fights like a dog twice her size and barks like a dog four times her size.
Thesis - Mastiff
Big sleepy looking boy who is described as "docile and dignified but also a formidable protector of those they hold dear" But I mostly chose this because their faces remind me of him.

Duenna - Saluki
I googled "Posh dogs" and the description of this one just is her whole character: "graceful, very loving, and good with kids. They can have a stubborn streak, though"

Motif - Dachsund
Originally bred for serious work but over time just got to be known for looking ridiculous and being used for stupid Sh$# like this:

Sequel - Golden Retriever
Three reasons:
1. they are very tied to movies, and so is he
2. They are companion dogs and Sequel is forever Motif's companion
3. Spoiler!
This one looks like him:
