Here are a few comments on your current plan. It is, as others have pointed out, a big program for seven days. Most of us prefer to spend a couple of nights at each of our stops so that packing and unpacking are minimised. We still drive on the day in between but the drives are shorter and focus on specific sights that we want to explore in more detail. Your plan will likely result in one night stops and all the sightseeing done while on the road or at the beginning and end of each day. That sounds exhausting to me but it could be done. As you are relatively young you should have the opportunity to do many more EDs and see all the sights that you can dream of. Why not limit this ED to the things that are of most interest to your father and sister.
If I were to select what to eliminate they would be:
Schellenberg: I have not been there but there is a lot of "Sound of Music" sightseeing to be done around Salzburg - most of the major sites I think. Also by going to Schellenberg you are missing the most beautiful parts of the German Alpenstrasse.
Jungfraujoch: I would only skip it if the weather forecast for the area is bad - check the forecast when you get to Neuschwanstein. Otherwise it is a spectacular site, but it will occupy the best part of a day - not counting the time getting there and back.
Baden Baden: But that is because spas do not appeal to me.
Ulm: Only because, if you see your friends in Erlangen when you are traveling by train, cutting out Ulm will eliminate a big loop.
I think that I was the one who recommended the drive from Koblenz to Cochem, but only if you take one of the routes along the Mosel River. Those two roads, one on each side of the river, go alongside vineyards, castles and pretty little towns. Google has routed you on autobahns. I have a lot of difficulty getting Google to route me along the roads that I want so I understand how that happens, especially as you would have to exceed Googles' limit of 27 points! So I would only go to Cochem if you decide you have the time to travel along the river side roads.