The first question to resolve when you have a generator is this: Is it a separately derived source?

NEC Article 100-1 states that a separately derived system can’t have a direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.

NEC 250.20(D) provides further detail on what constitutes a separately derived system. In this configuration, the 4-pole switches make the generator a separately derived system.

NEC 250.24(5) FPN requires you to have a neutral-ground bond at a separately derived system. This generator is missing that neutral-ground bond. Note that if this configuration had 3-pole transfer switches, it would not be a separately-derived system and therefore a neutral-ground bond would violate IEEE-142 and NEC NEC 250.24(5).