Without getting into the grounding issue on the output side of transformers, the first thing that caught my eye in your schematic is that you have the outputs of the two transformers directly paralleled, but since you are running these from two 30 amp shore-power cords, and normally, these are are 180 out of phase relative to each other, things could get very exciting when you plug them in, depending on how the wave-forms at the two secondaries are (either in same phase relationship or anti-phase relative to each other). . In addition, and perhaps of even more importance, your schematic is liable to get somebody killed. For example, the secondary winding of transformer #1 is connected directly to the secondary of transformer #2. Bearing in mind that one-to-one transformers "work" equally well in either direction, this means that the minute you put power on to the primary of transformer #1, it will energize the secondary of transformer #2, and that will in turn energize the primary of transformer #2 and electrocute the guy working on the shorepower leg that he thought he had killed at the breaker. Here you could very well be making "hot" the "shore 2" in your diagram. Strongly suggest you get some help on the project.