With that said however, all of it are within the FIA overseeing the deal, meaning that if one of those parties cross the line, FIA or/and F1 management can fine the manufacturer involved or/and making legal action against PD or any developers involved.Licensing single F1 cars has nothing to do with the 'strict' full F1 license. The car is licensed directly from Mercedes and can be freely included without involving FOM or FIA as long as it isn't used alongside other F1 cars to create an F1 race.
One manufacturer limit and any other restrictions is there for a reason.