Nanoha is still training new recruits and scaring the ever-living hell out of them. She and Fate now live in a nice apartment (read: the top ten floors) of some big expensive apartment building in Midchilda's central district. Fate is semi-retired/on leave because she wanted to take time out to take care of Vivio during her formative teenage years.
Subaru is slightly less hyper and slightly more confident after the events of the third season. She now works as disaster emergency response, and also helps out at the rehab clinic with her "sisters" and Ginga occasionally.
Tiana is still a tsundere. Enough said.
Caro et al are now so far off the plot radar that not even the writers know where they are. And a good riddance.
Hayate still hasn't conquered all of known spacetime...but she's getting there.