But I don't know if the Impel down guards were purposely made to awaken their DFs/ or the process was catalysed with help from Vegapunk or someone else by virtue of their roles as guards of a prison governed by the WG.
You said it himself, my though is the same, the zoan impeldown guards where different, as if they couldn´t transform back anymore. Like a smile user can´t transform his body to his normal form. I really think they just forced to use the awakened form, probably less powerful and with the drawback of not transforming back to human forms, via Vegapunk helps, so they had awakened zoan but not because they awake is own their own but with vegapunk help, because that they get less power as what they could get if they awake it own their own.
Also I think the awakenend zoan form have a drawback similar as what Chopper has with his monsterpoint.
Meaning using awakening only for 30mins or 1hour.
So I think the impel down guards where not the usually awakenend zoan but get forced via Vegapunk scienst.
I'd say that if we go by the scenario of an incoming temporary setback for the alliance and the fact that they were all prominent ex-captains, I can see their fruits being awakened. If not, then I don't see it happening.
If a flyer could have awakening I would bet on WsW, well im not sure about Ulti and Pageone since they are still young, about Sasaki and BM I don´t know either.