can python 2.7 be removed completely now?
A lot of application still require Python 2.7 and are not yet compatible with Python3. So it really depends on what you do on the server (Only running Django?).
One solution would be to use virtualenv so that you do not depend on which python version is installed in your server, and you totally control all the packages.
Look for django + virtualenv, you will find a lot of tutorials.
I am on ubuntu 15.10. I notice that i have many python versions installed. Is it safe now to remove 2.7 completely? And how to make 3.5 the default one? I ask this because i think it messes up my django installation because django gets intsalled in share directory.