I am not fond of your first or second system.
The way you have drawn up the use of your dual Racors is not how they were intended to be used. Their purpose is to quickly be able to switch fuel filters without introducing air into the fuel line...for one
device that burns fuel. The solution is to get a second set of fuel filters for your genset.
Each device that burns fuel needs its own set of fuel lines and fuel filters. The reason is that if for the example the genset has a vacuum leak, then the air entering the fuel system will flow back to the filters and then shut down your propulsion
engine. What you don't want is for crud in the polishing system filter to be able to shut down something else.
Completely separate fuel lines and filters starts at the fuel manifold (if you have two tanks
and a cross over) or if you don't have a manifold, at the tank itself. Don't share your fuel filters between two or more different devices that burn fuel.
The same goes with fuel polishing. A fuel polishing system should not be tied in to a generator
engines fuel supply system.
is the key to prevent the failure of one system from shutting down another system.
I know some have tied all their devices that burn fuel into one set of fuel lines and fuel filters, but I am looking at it from what is best from an isolation standpoint.
To draw up an extreme example, without isolating your fuel systems, you have the potential of shutting down your two main engines, your genset and your diesel heater, all at the same time if you get a vacuum leak or something else happens.