Switzerland

First you need a map. See here for a rail map of Switzerland: https://www.sbb.ch/content/dam/infrastruktur/trafimage/karten/karte-sts-pass-gueltigkeit.pdf
How many nights do you have? Until you say that, it is not possible to say what is or is not practical.

Do not stay in Zürich, you will be wasting precious time. Go direct by train from Zürich airport to your first destination (Luzern or Grindelwald).

Titlis is an easy day trip from Luzern.

Jungfrau is an easy day trip from day trip from Grindelwald (or other places in the area)
"Oberland" is just German for "highlands. The "Berner Oberland" is the region which includes Jungfrau, Grindelwald and much more besides. For a panoramic map of the area see here: http://www.regionalpass-berneroberland.ch/assets/karte-und-partner/Regionalpass-Panoramakarte-2017.pdf
Interlaken is on the edge of the area, there is no point in staying there if you are staying in Grindelwald.

Zermat is in a totally different part of Switzerland.

Well Grindelwald, Jungfraujoch, are all in the Berner Oberland, so that is 3 in one. If you want to see Grindelwald, why not just get a hotel there. The train to the Jungfraujoch departs from there. Don't stay in Zurich, its just a big city and you can be in Luzern in 1 hour on the train from the airport.

Having just left Zurich last week, I can agree to going directly to Lucerne. Zurich is fine if your son lives there, (mine does) but having spent 5 days in 2013 attending a conference in Lucerne, it is much more pleasant of a city to explore.