The way I've seen it work is that the PoC defines the features, then the dev team breaks this down and implements it any way they see fit. It's up to the teams

The way I've seen it work is that the PoC defines the features, then the dev team breaks this down and implements it any way they see fit. It's up to the teams to maintain their best practices and interoperability of the different solutions. Whomever built the PoC doesn't face any of these constraints, their focus is to help finalize the functional spec.