Summons wont do you any good on the battlefield. These ladys, or firebirds, may work as a trick against an early enemy thug, but overall its a waste of magetime. Alconosts are good though - they can smite, boost morale etc. And Gamayun are ok mages, though golems are arguably a better investment.
Beregini are a summon I really liked though. With water and earth on my combat pretender, I can summon one and get a nature 2 mage - it's absolutely great. And she can make clam rings, amongst other things.
Order 1 is not enough, Bogarus needs lots of money... but that can be helped now.
For old mages, con 6 and boots of youth should do the trick.
Troop-wise, you've got cheap archer, and you can buff them with flame arrows and windguide - they can deal quite good damage then. Also, you've got malaya druzhina cavalry - if you dont use CB mod which castrated them for some reason, use them as heavy shock troops, they are very decent.
Peshty spearmen are easy to mass and have strat move 2; if strat move is not an issue, city guards are also not that bad. Not good, but not bad as well. Dont expect infantry to start actually killing things though.
They are meat shield.
And you have mages. You absolutely need second castle to recruit more mages. Astrapelagists can join communion. Script them for slave-precision-thunder strike x3. Last astrapelagist should be master-power of the spheres-thunder strike x3. And splash one occultist with a bow, scripted for master-shoot-shoot-shoot-reinvigoration-shoot closest enemy. Cheap and evil communion.
Outside communion, occultists can cast nether bolts / nether darts, quite an evil spell.