Thank you for your thorough response on this. I believe we have had the same doubts but needed some expert advice and guidance to figure out the next step.
Regarding my scenarios, its pretty much a simple approach at this stage as we are just trying to load/read word/excel (maybe even powerpoint documents) in a native reader (for reference, check the syncfusion controls for doing the same). Additionally, if the user performs any annotations on top of the documents we can then retrieve these changes for viewing later on.
I believe this scenario is somehow partially or fully supported in WPF paradigm, not so much in UWP. I hope the anniversary edition is going to come about with a lot of enhancements in that regard. But until then, i believe we have to find an alternative and hope for the best in your upcoming roadmap for UWP or MS Redstone release soon.
If you can offer any alternatives we can use (that could be offline rather than online driven), would be much appreciated.