a. You should be discussing this with your SAP Account rep.
b. You should be discussing this with your SAP Account rep.
c. Yes. You can use OpenUI5 and do this quite easily for non-SAP apps and/or use Gateway+SAPUI5 for apps that "expose" SAP data for non-SAP "users"....heck, you could even build simple ABAP web services and expose them to consume however you like for whatever user(s).