<<"Can you advise an ideal itinerary that covers most of the major attractions (Rigi, Pilatus ,Stanserhorn ,Mt Titlis,Jungfraujoch,Schilthorn,Rhine Fall) and also what should be an ideal location where we can base our stay so as to avoid constant transfers with luggage.">>
You are early enough in October that snowy weather is unlikely to be a major problem. Can happen; unlikely.
The logical bases for your goals are Lucerne (forgive me if I slip and spell it Luzern.....that is the spelling in German, which is the language of the region) and the Jungfrau region to the south of Interlaken. Towns such as Wengen, Grindelwald and Mürren come to mind. Interlaken by itself is better as a transfer point; the real scenery is south of there.
Look at a map:
Info on the areas:
The Rhine Falls are an outlier, from a geographic perspective. Consider seeing them on your last day before you fly out . That will be easy to organize, especially if you come from Luzern or stay near the Zurich airport. (The airport is as little as one hour from Luzern.).
This link will help on that:
I'd also have a very mild preference for the Berner Obeland/Jungfrau Region first, from a weather perspective. However, weather in that region is very changeable, and if you want to go up to Jungfraujoch, leave flexibility and keep an eye on the weather forecasts. If it is cloudy up top. the cost of the view of the inside of a cloud is a bit high.