The only issue is with charge controllers. If you have solar controllers they will not be able to do anything about the wind turbines or any other charging source. Best way is one large dump controller capable of handling the total charge current.

A problem arises if the solar uses a mppt converter to maximise efficiency as these generally include charge control facilities. If you can set this above the dump controller you can let the dump controller look after the charging programme.

I would only regard the engine as back up. If there is no other charge available then you have to use it to fully charge but if there is wind or solar then use the engine to get you through the bulk charge and let the wind and/or solar do the final stage via the dump control.

I see no logic in running an engine generator and taking the final and slow part of the charging stage via a dump regulator, it is just wasting fuel.