while i hold no love for the rheinlanders and especially the WRF open war with them sounds like a bad idea so openly allying with Bretonia isn't smart but I'd say support them unofficially. as far as the hessians go once more supporting them onofficially would be the way to go.
but all in all we should try to get the war over with.
so in short: * Military support for: Bretonia unofficially
* Political support for the Red Hessian cause: Yes once more unofficially
* Attempt at brokering a ceasefire and diplomatic resolve of the conflict: Yes