First and foremost is just probing on the application, trying to understand the technology the app is built on. Then validating, if the tool does support the technology, any issues work around etc. This would give u a clear picture on should u automate or not?
Then on the framework part, i feel more to do with the expertise one holds(Reuse existing framework). Also it depends on the type of application, the user anticipated to be supported and the complexity of the app.
Process for automation is more intrinsic for each organization!!
Interview : I think, if you have worked on the tool u'll be able to put forth all that is required. Just get the basics intact, all the best!! As I have not been 2 any pure QTP interview, so i might be of little help.