Thanks.
1 - Android has a system service that stores contacts. Aqua can autocomplete contacts from there (as other Android mail apps do).
Aqua also has a built-in contact picker where you can pick:
- For Exchange / EWS accounts, server side contacts
- For all types of accounts, addresses from recent send and received messages
You can bring up the built-in contact picker using the buttons to the left of of each recipient entry field
2 - Yes. Messages can be shared to: EverNote and such, printed... attachments can be uploaded to DropBox etc.
3 - The app tries to auto-detect hosted email accounts, including those at Office 365, but it's not quite perfect, depending on network connectivity (there is a time limit on how long on the DNS MX query).
If you think your connectivity was good at the time, feel free to drop me a note at kmansoft / gmail, and include your Office 365 domain name so I can check.