Just realized I didn’t answer your last question.
If you are only ever going to use ACF on one site the just buy a license for that site. I think you’ll find after the pro version that you’ll want to use it again if you are a developer. I think that the dev license is well worth the money. ACF is not like some of those other plugins that make you keep paying them every year to get updates, you buy the dev license once and it yours forever.
