Hello Lijerrue94
Please take a look at the validity map for the Swiss Travel Pass. As you see, some destionations are included, some are available with a 50% reduction and some are not included (for example, Matterhorn Glacier Paradise and the funicular railway starting from Jungfraujoch).
Since you are going to spend about 5-6 days in Switerland, the Swiss Travel Pass is probably the best option because it includes almost every mean of transport and allows you to travel without the thought of buying a ticket (obviously, with the exceptions of special destinations that you can check on the validity map).
The Swiss Half Fare Card is also designed for international guests, but you will always need to buy a ticket before every trip.
The Berner Oberland Pass does not include the leg from the airport to Zermatt, so it does not really suits your travel plans. Here you will find the validity map, so that you can compare it with the Swiss Travel Pass.
Here you will find the links to the official websites of the mountain destinations you have mentioned:
I wish you an amazing stay in Switzerland,
Chiara_S