Mine's got my Onedrive mapped but it's a bit more flaky and clunky than using the Google Drive as you'd expect, however that's probably because mine uses Multi Factor Auth as well.
You need to download the app to connect One Drive but once it's done it just appears as another drive once you're signed in, and to be honest it's a single click install, so no hardship.
Spec wise, you need less than you'd think, I went for a dual core Intel Celeron one with 4GB of RAM and 64GB eMMC storage, expandable with an SD Card if I need more local, but I've also taken advantage of the years free additional space in Google Drive that I get with the device
, 100GB instead of 15GB, and I've got a network server at home with nextcloud that I set up, and that's got 12TB of usable storage
I suspect you'd do well with half the eMMC storage but I'd aim for 4GB of ram, and something intel CPU based as they're more energy efficient than the other stuff out there in my experience, and battery life and portability is the key really.
Oh, and try and get a newer one, as they have the Google Play store meaning you can run Android Applications native on the OS, makes them a lot more useful in my mind.