I didn't go throughout the frameworks, but I imagine this scenario:
Backbone is the main platform. You'll use it for pretty much everything except one thing "templating". Knockout will fit well with templating. The example that is present in the home page is what I think of. This will help separate the two processes. I'll have two different files reducing the complexity of each one. jQuery is the rescue when dealing with other DOM issues, animation and also AJAX.