cyborg, your plan seems pretty good as far as skills, just one quick thing. The a3 merc that heals is the bloodmage and he is fire and poison based. I would focus on fire spell dmg runes as Ort runes will do nothing for him. Obviously once you start gearing the merc for real go for high def fascinating crafted sacred pieces and socket them all with kra runes (fire pierce).
Also, I disagree about parasite being shite and about dagger/shield being bad. Parasite works just fine for clearing with enough damage and, while leveling, a 2h scythe is better, dagger plus shield is amazing for end game and ubers. The defiler ssu dagger is a game changer for dagger nec, it makes parasite truly powerful and the deathlord morph is amazing. Just some thoughts