As far as I can understand, you have a scenario, in which a Template is defined for an element. Initially, the parent element has no source bound and the data is loaded later with an AJAX call. If this is the case, you will need to pass the data from that call to a property in the ViewModel:
Here you will find a simple implementation of the above suggestion
Concerning the second question, in order to successfully bind a source to an element, you will need to use both data-bind="source:..."
and kendo.bind(..., ...)
Further information on source binding in Kendo MVVM could be found in our Documentation