I haven't followed this thread... so, maybe my ideas are already mentioned... but,
take the 600 vampires... and make with the 100,000 humans and x hobgoblins, 100,000 + x + 600 vampires
hit the anti-undead squads first... with so many vampires who can multipy themselfs, use globes of continual darkness (a lot of them) to keep it dark (advantage for undeads, fighting in darkness vs blinded opponents) and LET'S MAKE MORE VAMPIRES
.
Also nice to see your friend turning in a vampire. It destroys morale.
Im also a fan of fireworks and summoning... everyone must love the large area of effect spells and the maralith (animate dead at will)
And if nothing works pray and run away!
im out... to think of more
take the 600 vampires... and make with the 100,000 humans and x hobgoblins, 100,000 + x + 600 vampires

hit the anti-undead squads first... with so many vampires who can multipy themselfs, use globes of continual darkness (a lot of them) to keep it dark (advantage for undeads, fighting in darkness vs blinded opponents) and LET'S MAKE MORE VAMPIRES

Also nice to see your friend turning in a vampire. It destroys morale.
Im also a fan of fireworks and summoning... everyone must love the large area of effect spells and the maralith (animate dead at will)
And if nothing works pray and run away!

im out... to think of more