How to get around in San Francisco - Clipper card questions?

Hello,
Family of 5, the youngest is 13. We've all got phones.
As we've got a car, we're avoiding staying in the city centre and got a hotel over in Oakland.
I see we've got quite a few options for getting over to San Francisco (BART and ferry) and once we're over there will be mostly using MUNI and will do one time on the cable car.

Now I believe the easiest way to do this is to add the Clipper Card to each of our phones. I've tested that with mine and it seems to work and I can potentially top it up with my credit card.
Now how does this work on my boys phones where they don't have any cards listed in their wallets? Can I somehow link it with a Clipper account and set up a family thing? Or *shudders* do I need to set up my credit card on each of their phones? I see the alternative is to buy a physical card ($3) but how is that topped up?
Also if we've got credit left on the Clipper at the end of 4 days, how does that get refunded?
(remember everything for me is multiplied by 5)

My wife also loves Chinese foods so any suggestions for dinner in Chinatown gratefully received.

Sorry for all the questions! I suspect it'll all become apparent when I get there. I've also never used Oyster, I guess they're the same thing.

[mitchja]

I’ve had a Clipper card in my iPhone Wallet for years. You can top them up using the clippercard.com website. Not sure if you can set them up though from the website? You will need to set up an online account first.

I started off with physical card and then later transferred it to an Apple Wallet version and I remember buying the original physical card from a ticket machine on one of the platforms. Pretty sure you can top them up using the ticket machines as well.

Have a look at the clippercard website as there’s a lot of info there about using the card.

There also an app.

I’m not 100% sure, but you may find that any credit left on them may be none-refundable. It’s doesn’t seem to have an expiry date though as my card was last used in 2022 and still shows I have available credit on it!