What's the best train pass to buy for 2wk Switzerland Itinerary?

Minimum cost would be 2 30-day Half Fare Cards at 120 CHF each and a free Family Card for the child.
St Moritz on the Glacier Express is the most expensive, and I did not consider the reservation fee, which has to be paid out of pocket regardless of pass. I also assumed, that since riding scenic rails seems to be a priority, the 1st day from Zurich airport to Muerren is by way of Luzern, which takes a little longer, but is actually cheaper than by going through Bern. Also assume that July 19 is Muerren to Zermatt via Kandersteg.

I went on the assumption that you would get a 6-day Berner Oberland in Muerren and a 3-day Peaks Pass in Zermatt. If you don't get these, I still budget the same amount for full fare tickets while you are there. The 6-day Berner Oberland Pass is 310 CHF without discount, but 235 CHF with a Half Fare Card or active Swiss Pass. The Zermatt Peaks Pass is 220 CHF without discount. There is a discount with a Half Fare Card, but they don't say what it is since it has to be bought locally. Assumed it was 25% discount like the Berner Oberland Pass.

The 15-day Swiss Travel Pass is the most expensive way to go, but perhaps the most convenient. The next most expensive way is a 4-Day Flex pass. The Half Fare Card wins again for least cost.