In a quiet corner, Winslet is cackling to herself, with and evil grin on her face, plotting your doom. :D
Sounds like they are doing well, overall.
The 2 cats I adopted together 4 years ago will both groom each other at the same time. I call it combat grooming, since it often devolves into a furball, and then back to grooming. "You WILL be groomed. Rawr!"