Here's a start.
I 'm not where I can easily check timetables, but you can look at the timetable:
<<"Day 1 Depart for Schaffhausen and see Rhine Falls and Zurich city">>
The Rhine Falls are not so special in the winter. You might choose to make that part optional.
It will not take a whole day to explore the most essential parts of Zürich, even though there are many cultural things which make staying in Zürich for a long stay rewarding.If you like museums, there are some fine ones. You could get to Interlaken that night easily. See note for day 2.
<<"Day 2 Check out from Zurich and take train to move Interlaken">>
That process (train trip) will take about about 2 hrs, with a train every 30 minutes at xx02 and xx32. Change at Bern.<<"Day 3 Check in Interlaken and take train to Jungfraujoch and visit Konkordiaplatz and the Aletsch Glacier">>
You can start that on Day 2. This requires some checking, but I recall that Konkordia platz is in the middle of the Aletsch Glacier. If I am correct, that will take either a technically difficult hike with a guide, or (if available) a helicopter flight.
I hope I am wrong.
You could consider Schilthorn if you expand your stay in the region, especiall if you stay south of Interlaken.
Give some thought to staying in Wengen , ( possibly Lauterbrunnen), or Grindelwald, instaed of Interlaken. Interlaken is better for rail connections to the rest of Switzerland, but is not much of a destination for tourism.
<<"Day 4 Take train from Interlaken to Hergiswil and then Hergiswil to Engelberg. Engelberg is the lower part of Mt. Titlis.">>
Where will you stay? I suggest Luzern, unless you want to be in the ski-village of Engelberg.
<<"Day 5 Have trip to Lucerna and Check in Zermatt. ">>
Better to stay in Luzern. The trip to Zermatt will take between 3 and 4 hours.
<<"Day 6 visit Zermatt ,matterhorn and schithorn">>
If you mean "Schilthorn", that is near Interlaken and Lauterbrunnen and Mürren.
<<"Day 7 Check out from Zermatt and move to Zurich to catch flight">>
What time is your flight. Intra europe or transcontinental?.
<<"Please suggest if it is doable or adjustments are needed">>
Those are my first thoughts.
You have laid out a very nice trip, and the adjustments will make it better, in my opinion.