Do Drupal 8 / backbone.js have conflict when using AngularJS on top?
Seems like Backbone.js and AngularJS don't have conflict if used in the same page.

So one can ignore Backbone.js existence and do stuff with AngularJS.

Still there might be better ways doing this in future since D8 is still in development as I post this.

And for curly braces conflict with Twig in AngularJS we can config interpolateProvider service explained here