Only to a limited extent. The Archon’s army will after all be bringing more high-INT resources than you have at your disposal.
Both will be possible.
And probably 50 bows. Radmar is advising you to trust in his and Simon’s combat experience (and Elery’s and Zvad’s, if they’ve survived), not your own. I agree that it makes far more sense for your character to hide in the helots or run, but Radmar’s brashness is I think not utterly insane, even for your playthrough.
As for zombies, Ghaesh the Archlich won’t try to get you to join him for a few games yet.