There are vending machines in major train stations that dispense cards and do refills; you pay with cash. There’s usually a bank of machines before the ticket gates so they’re easy to find, and most come with at least English, Chinese, and Korean foreign language options.
Yes, but it’s easier just to pay cash at the Keisei ticket counter.
If you have a fare card, you can use it or cash to pay for a ticket.
On our first trip, we bought Suica cards from the JR ticket counter in Narita and used those to buy tickets into Tokyo, and on subsequent trips we’ve just paid cash and used the Suica cards for subways and local trains.