I actually didn’t check anbox when I had 16.04 installed for a couple of days. My impression was that not much works at the moment and in the Ubports welcome room at Telegram someone told me to wait at least a month before using 16.04 on the FP2.
What I tried can be found here: UBPorts 16.04 updates + feature tests
The next OTA update for 16.04 doesn’t have a due date yet: https://github.com/ubports/ubuntu-touch/milestone/7
But I can’t say if that version is supposed to already support anbox.