How much current do you think the bicycles will draw?
The generator can charge both banks but the solar should be able to do a better job than the converter that came with the coach. A good solar controller will charge at a higher amperage and maintain the batteries much better for a longer life. You don't have to have all the same batteries new at the same time but if there is a week battery it will be a draw on the rest of them. You could put in the isolator but it will mean the solar would not be charging the isolated array obviously. BTW, those amp hour ratings are to sell batteries so I wouldn't rely on those numbers too much.