Hi Ashwani -
Don't know where you are coming from, and what time you arrive at Zürich Airport. However, you have set a very full day schedule for your arrival day, and if you are tired or jet-lagged, it may prove difficult. In fact, it may be impossible to fit all that in to one day, unless you intend to arrive at Wilderswil very late.
Even so, both the Rhine Falls and a lake boat ride at Luzern will be very difficult to accomplish. The route to Wilderswil via Bern is faster than the route via Luzern; that would be one way to save time. A lake boat ride will add significant time.
Please check the timetable linked above for your train travels. Lake boat travels are included in the time table, but it may be easier to use the timetables published by the lake boat company.
Scroll down to make sure you get the right dates...the schedule changes with the seasons.
And, if you scroll down even further, you can find a link for a map of the lake. It is upside down....north is at the bottom.
I prefer this map, which can be set to show train stations, etc.
map.search.ch/?x=11160m&y=20656m&z=16 &poi=parkhaus,viasuiss e,zug
Here are some useful links-
That link discusses lake boat rides.
Here is a link for the Rhine falls, including how to get to them:
The Rhine Falls are powerful and impressive. But, if I had to make a choice between Luzern and the Rhine Falls, I'd choose to spend the time at Luzern, even if it were only a short time. There are many waterfalls all over the world; there is only one Luzern. It has a tremendous variety of scenery and an attractive old town. Once you study the time tables, you may find that you wish to make a choice between the two of them....or neither. You might choose to go directly to Wilderswil.
I have attached a few pictures from Luzern and the lake. The third one shows a peninsula called Bürgenstock, easily visible from Luzern lake shore, with an arrow pointing toward the location of a mountain restaurant called Hammetschwand. The views from up there are great. You won't have time to go there, but I'm showing the pictures taken from up there to give you an idea of what the surrounding countryside and lakeshore are like.
There are lots of pictures of Luzern itself on the internet, in addition.
Your time in the Jungfrau region is good, because it can be flexible, and, once you are there, you may chose to add or subtract some item. There are plenty of things to choose from.