My current dogs are a big factor in my decision regarding the next dog.
I'll be completely honest here. If it were just Grace I would want to get a puppy. Because she adores puppies.
She is twelve, but I know she would still enjoy a puppy in her life and I would just make sure it didn't become too overwhelming.
I personally would rather an adult dog or older pup for myself. But seriously, having Abby come into our lives as a pup was one of the most joyous times in her life lol. If I could give her another pup, I would. And I would be fine to raise a pup, I know the effort required and I would do it to the best of my ability. I just like adult dogs better is all, as cute as pups can be.
Grace is very easy going and gets along with most other dogs so I would be open to many more possibilities with her.
With Abby, which is the most likely scenario because I won't have three dogs and Grace is the oldest one, I would have to take into account her dislike of in your face dogs. I'd get a confident, well-adjusted, small, adult dog.
In both cases, I still have heaps of choice and I don't have my heart set on a particular breed for nextdog, in fact I envisage a rescue mutt of some description. Unless the unlikely happens and Abby falls off the perch first... then I may just have to get a purebred puppy for Grace. (I am not keen on the idea of a rescue pup, happy with an adult though).