Hello,
Running Anbox will only be possible when 16.04 will be released. At this time there is no release date, and Anbox doesn’t run on Ubports 15.04. You can check the milestone progress here : https://github.com/ubports/ubuntu-touch/milestones.
If you wish, you can try 16.04 with the Ubports-installer, but expect (a lot of) bugs !
Cheers 