Yes.

Yes, certainly, as could very easily been seen on mainsite. Pass includes all countries west of Russia/Byelorus/UKrayna/Moldova.

BUT do note that Swiss has dozens of different railways, some quite small-just 1 line going in the valley and also loads of all types of possible means to go up many of its famous mounatins. Many of these-ALL that are just for pleasure going up and a fair lot of the others do not accept the pass or only give discount on very high fares. Notably those south of Interlaken where USAers like to go so much. But there remain some 30+ that do, incl the one to Zermatt, which seems now to have taken the crown of best beloved place to go to.

Here you can check which railway companies that are included in Switzerland. 

https://www.eurail.com/en/get-inspired/trains-europe/useful-train-information/participating-railway-companies

Apart from the Jungfrau-region, where Eurail gives a 25 % discount, you can travel for free with Eurail on basically all routes. There are some scenic trains with mandatory reservations but there are reservation free regional trains on the same routes.