Angered that his efforts barely even bought time for one combatant, Belaver turns on the air elemental, directing his own elemental to attack it as well.
Belaver will provide Toriah and whichever of {Torn, Craven, Raner} has the lowest AC with Barkskins; he will lend a Fog Cloud and Cure Light Wounds to Kerwyn, if desired.
Belaver steps away from the troll and summons up a dire weasel (dropping the Remove Disease) behind Slaazh, hoping it can be coerced into giving up Lylamwyn before the mage is injured.
Belaver will probably be delighted to be able to free up some of his spell slots for non-healing applications. Or, given the way things are going, simply to have to replenish those healing spells more often.
Belaver snarls and does his best to spear one of the heads; he'd normally try to give it more targets than it could handle, but that doesn't seem like an effective plan here.
"I'm not so sure about that. That serpent-thing is unlikely to tolerate other guards nearby; if we head in the other direction, we won't know what defenses are waiting for us, but there's sure to be something."
"It may be that our course of action is to avoid the orcs, with Toriah scouting ahead to warn us of ambushes. They prefer to attack from prepared positions; if we avoid the ground they want to fight on, they may not pursue us."
If the wagon draws too close, Belaver will assume the form of a Medium viper to slip under the wagon, then strike at the archers' heels. If the party instead heads towards the direction they're being herded, or retreats, he will follow.