Hi,
krpano doesn't output in Flash OR in HTML5, krpano generates images and xml that will be viewable by the krpano Flash viewer or the krpano HTML5 viewer.
That means the output itself is the same for both viewers and depending on the html5 setting the .html file (and the system/browser you use) either the Flash viewer or the HTML5 viewer will be loaded to view the tour.
You can see a comparisons here:
http://krpano.com/docu/html5/#intro
Basically you shouldn't need to matter about Flash or HTML5. The default is HTML5, Flash will be only used when using HTML5 is not possible (e.g. on old systems or locally with file:// urls in Chrome).
About lifetime license - the current license is vaild for all 1.x.x version from 1.17 and up.
About Panotour Pro - Panotour Pro and krpano are two different programs from different developers. The way both software tools are working can be very different (e.g. usage, image generation, html/xml design) but both are using the krpano viewer to show the final output. A license for Panotour Pro also includes a krpano license.
Best regards,
Klaus