[thejeff]

Note that Northern Star, communions, or any other kind of boosters don't help with Mind Duel.

Seithkona are cheap mind duelers and thus make a good counter to the large Astral mage forces. If nothing else they're a good deterrent.
LA Arco doesn't have a lot of strong Astral mages. Lots of 1s and 2s, but they'll have to have boosters, buff or communion to Soul Slay, which gives you a little leeway.
Your Skratti thugs make good raiders. They're not quite so good against large mage supported armies, but that's true against all but the toughest SCs.