Q: payment info

see this article

Change or remove your Apple ID payment information - Apple Support

Do any of the scenarios on the 'if you don't see None or can't select it' link on that page apply, or are you a family organiser in family sharing ?

It won't show if any of those scenarios apply (you don't owe iTunes, have a subscription, not a family organiser... ?). When are looking for the 'none' option ? You won't get it when trying to download something, it will only potentially show if you just log into the account