Should we see Mount Pilatus, Mount Rigi, Shilthorn and Jungfrau?

I got back from a RS Best of Switzerland tour a few weeks ago. We had great weather and were able to visit Mt Titlis, Schithorn and see the Matterhorn in Zematt.

The guides basic approach is to "make hay when the sun is shining ". Because the weather can be volatile you don't want to pass up to many opportunities. Of the ones you listed I would choose the Schilthorn. Incredible views, you can see the eiger , monk and jungfrau. Bond world is pretty fun too.
We stayed at a hotel in Murren that's owned by the same organization. That offered us the option of having breakfast up on top of the Schilthorn. It was fabulous fun but I'm not sure how much I would have elected to pay if it were optional. Jungrfrau takes longer and is more expensive.

How much would it all cost just curious?

From the RS guidebook.

Stechelberg to Schilthorn lift is 80 CHF

Jungfrau Joch fro Lauterbrunnen is 184 CHF

Mt. Pilatus lift is 72 CHF

Mt Rigi is 68 CHF.

All round trip full fare prices, I'm not sure what discounts may apply.

We will have a Swiss Pass. So I think some will be discounted. Anyone know how much these cost for children?

You have to search each mountain by name. They list all the prices.

I think with Swiss Pass Pilatus and Rigi are free. Schilthorn is 82.50 for adults, 41.10 for a child and Jungfrau is 158. Correct me if I am wrong?

you are correct
the Swiss Travel Pass covers Mount Pilatus and Mount Rigi

https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html

Do you recommend seeing them all?

I would not see them all even in ideal weather. I get more enjoyment out of a great alpine day from a hike rather than a mountain peak excursion. Perhaps do one excursion per area: either Pilatus/Rigi or Schilthorn/Jungfraujoch.

The Jungfraujoch is spectacular but it is very expensive, very time-consuming, and very crowded. I'm glad I did it once but I won't do it again.

If your children are under 16, get a Family Card with your Swiss Pass ( it is free) and the kids will travel with you for free.