Re: FIORI App or FIORI-like App?

to me your use case looks like a good candidate to be developed as an extended standard Fiori app. But take into account that I'm not an expert of the app Regarding points a and b, you will need to be more specific on which extension mechanism you mean. What I have heard from some customers is that before using WebIDE extending apps was quite challenging, and as they started using it this task became very easy.