You need to invoke the Apple Pay payment process in order to get the Apple-generated token. While strictly speaking you don't actually have to process the payment to get the token, what would you do with it otherwise? Store it? They're not re-usable and you don't get the card details to otherwise store a customer/card pair from it for future token generation. If you're not already familiar with it, I would strongly recommend reviewing the Apple Pay Identity Guidelines doc: https://developer.apple.com/apple-pay/Apple-Pay-Identity-Guidelines.pdf with respect to offering your customers multiple payment options including Apple Pay.
Yes, with Apple Pay the last4/exp values are disassociated from the actual card for security purposes.