Re: So I did have your earlier version working on Android P.
Um, maybe, but for me it was crashing on Android P emulator, and the crash was 100% repeatable / reproducible, I traced it to a specific change Google made in P.
Re: As to calendars, if I get an meeting invite/ appointment in my Outlook365 account, how does it get added to my calendar ? and which calendar ?
Exchange servers automatically save invites from incoming emails into your Calendar (also on the server) - and then those get synced to the phone by Aqua Mail.