Looks like you got yerself a cat. And I bet the owners will never ask if you’ve seen her.
No, little, in context here is certainly kitten sized but older kitten or perhaps just a smaller adult cat, only a little smaller than Miss Thang! who also seemed plumper. Thinking about it now, I wonder if maybe she got “got” and is now pregnant. Might that explain the touchiness about being picked up? I dunno, I’ve only ever midwifed a pregnant cat once, long ago.