<<"Weather permitting is it advisable with our 2 full days in Murren to do the Jungfraujoch one day and Shilthorn the other?">>
The Jungfraujoch and Schilthorn (note spelling) are very different. Whetehr one is better than the other is a matter of opinion.You can estimate timing from the timetable linked previously. What you sugest is quite possible.
Sunset is at about 1840. You may have more light on the Wengen slope than the Mürren side of the valley at sunset, because it is south and west facing.
<<"in sight-seeing the Alps and light hiking">>
Some consider this hike to be the best "light " hike in Switzerland:
Please resist the temptation to tag it on to the end of trip to the Jungfraujoch, and walk in the wrong direction
If you walk it from Kleine Scheidegg to Männlichen, you'll have to go back to Switzerland again in the future to do it in the correct direction. ;-) And I note that you may not make that trip. Sp, you would have a dilemma. ;-)
The effect of walking toward the Eiger, in the downhill direction, from Männlichen to Kleine Scheidegg is made special by the way that the north face of the Eiger towers over you as you approach it. if you walk it in the opposite direction, you have to keep turning around to see it, and you never get the same feeling. The Eiger is overwhelming and you begin to realize why it is called the Ogre ( in Swiss German " Eiger")
Others don't feel so strongly about that as I do, but long time members of this forum know how strongly I feel about this. If it matters to you, so does Rick Steves.
I have attached a few images of varying technical quality to help make my point.
By the way, I checked the timetable, and the cableway ( a large cabin lift , what the Germans call a "Luftseilbahn" is running on the days you will be there.
Take the train up from Lauterbrunnen to Wengen, walk 5 minutes up the main street to the lower lift station (technically and precisely at "Wengiboden" and take the ride up to Männlichen (technically and precisely Männlichen LWM station.). Once you are there, if you turn to the left, you can climb a steep train about 100 meters to the very top of Männlichen Gipfel (in this context, Gipfel is summit or peak) . Or, you can turn to the right, walk a few hundred meters to the restaurant, and grab a bite or walk on to Kleine Scheidegg. Bring a camera. Don't go up there to do the walk if it is cloudy; the inside of a cloud is not very scenic. The more days you can spend in the area, the better chance for clear weather.