Hmm, no EX Wiz Archer =/. Can't think of any alternatives besides maybe Enchanter, but that seems like a last resort.
I feel Foveontosa needs more tanky units than what you have, so I'd say take him out. He's too much setup and you don't have the frontline to protect him. Put in some removal instead, like as you said Withdrawal Strategy, Sweeping Tidalwave, and possibly Warning Knife. Also, I recommend an end game unit, Sorceror Monk would work.
As for your soul skills, I think you need more removal. Stuff like Distrier, Asuet, Sergis, Giant Arthreupolid, you get the idea.