About the marching order, I see three categories:
-Fighting people: Kellian, Kerwin, Mulch, Sniffer.
-Support people: Meldain, Pak, Mulch (again), Fixit.
-People that´s best just out of the fight: Zan, and to a lesser extent Rial. Rial has the advantage of spiderclimbing, so he can quiclky climb to a good sniping position, even is he´s in the middle ranks.
So, unless the rogues are scouting, I´d suggest the following:
10 ft:
Kellian, Sniffer
Mulch, Kerwin
Zan, Fixit
Pak, Meldain
Rial
20 ft:
Kellian, Kerwin, Mulch, Sniffer.
Rial, Meldain, Pak, Fixit
Zan.