There seem to be several techniques to implement this each with its advantages/disadvantages.
1)Use a inline script block. This would bring the template blocks with each page load. If parent page is non-cacheable, it could get heavy with multiple templates
2)Access templates via a global variable object in an external javascript file. This is cacheable but template strings become hard to decipher
3)Template strings come as a part of JSON response. This begs the question, why not server side templating?
4)Use a static iframe and compile the templates on iframe load - this is cacheable, templates are readable/editable, same-origin policy could be a problem if static elements are placed on another domain
I finally opted for the iframe approach, but am too inexperienced to be aware of all pitfalls.
Thanks