Hi Iffatt -
Welcome to My Swiss Alps.
Answering all of your questions will take quite a bit of time, which I don't have atthe moment.
However, here is a start.
Look at these links:
My next step would be to look at your routing on a map:
If you zoom in far enough, you can see rail lines.
If you go to the menus, under "Points of Interest, Traffic," you can turn on a layer with train/bus/boat/etc. stations.
Upon first reading, my thought is that you are trying to cram too many things into the time available. However, to back that up, and really understand it, I'd need to look at the map and find the journey times in the timetable. You can do that , too.
By the way, I am amongst the minority of visitors who don't think the Rhinefalls is worth the trip. many disagree, but that is my opinion. I've seen a lot of waterfalls elsewhere, and I'd rather see things that are more uniquely Swiss.
And, as a general rule, Luzern makes a good first stop. However, if you go directly to Zermatt upon arrival, you'll have some extra time to get the lay of the land and understand your sightseeing options. I could make your short stay in Zermatt more rewarding.