The utility connection is interesting but usually in a hurricane, they cut the power before the storm so the poles are dead. The issue is with a legal breaker interlock as your only "transfer equipment" so you are stuck with that utility connection.
You have a good grasp of everything you spoke of but the open question is can you have 2 MBJs?
Inspectors I know knee jerk "parallel neutral" but in this particular case, I don't see the hazard. There are twice as many paths to trip that breaker. The ones that are on are 15 or 20a so either path is plenty big enough in a 30a generator cord.
I bet way more than half of the 30a or lower class generators get plugged into a dryer receptacle.
