What kind of cats can our characters expect to encounter as they go about their adventures?
Lots of cats, for one thing.
While Englishmen may love their dogs, the English householder hated his mice and depended on cats to get rid of them. Defoe talks of forty thousand cats in London in the mid-1600s. "Few Houses being without a Cat, and some having several, and sometimes five or six in a House."
These London cats were working cats --
rangy, businesslike mousers and ratters. I see them dozing the day away in the kitchen, then rising in the night, roaming the house to do battle with vermin, meeting the enemy behind the plush curtains of the drawing room and down behind the sofas in the parlor. All the while, the gentlefolk snored in their beds.
But there were pampered, plump cats as well. We find them in paintings, batting at a soap bubble, peering into a fishbowl.
For the rest of the article -- including the breeds of cats you'd see in Regency London, see here