It looks like Adobe used to have documentation on these use cases [1]. However, I can't find the 6.5 version of this document. 1. Using the Adobe Experience Manager ContextHub to work with Personal Experiences
HTL is a front end (sure you hvae basic programming commands like looping, etc), BUT you would need to use Java as part of an HTL/Sling model to complete this.
Why do you have different pages being served from different AEM instances? For an AEM implementation, the best practice is for pages to be served from the same PUB instance.