What was the part that the errors are happening with Twenty Sixteen theme active that they didn’t understand.
We are just losing time back and forward.
Your WordPress Editor by default with Twenty Sixteen should look like this.
https://www.dropbox.com/s/e9etc08reo43hyd/Screenshot%202016-11-01%2016.38.26.png?dl=0
And yours don’t look like this because it didn’t load totally, this specific error got nothing to do with the theme.
We deal with several situations everyday and a few hostings have this kind of attitude a bit unprofessional in my opinion. You should consider find another hosting.
-Rui