Switch from PayPal Standard to Pro or Stripe

A client is on PayPal Standard but wants to do away with the awkward 2 step process. Is it correct that both PayPal Pro and Stripe would allow one step where a new member can enter personal and payment info on one page?

We have a lot of code that uses Paypal hooks. Would those have to change if we went to stripe? Do equivalents hooks exist for all?

If we went to Paypal Pro, could we use most/all of the existing code/hooks?