I wrote something on that a while ago: https://linmob.net/2020/08/15/anbox-on-the-pinephone.html

(I’ve since switched to ArchLinuxARM (and published several videos on how Anbox runs on t he PinePhone on YouTube) and won’t go back unless that breaks, so I don’t know what the current state is on Mobian.)

It turns out Anbox is already in the repository 2020/05 version) and ashmem and binder are in the kernel already.

The keyboard seems like a problem, but a USB keyboard works fine in Mobian; it just needs to find its way through to Anbox.