When bringing in a card with Necromancy's effect... does one have to pay the cost of the card once more? I presume one does?

Yes, it's just like you are playing it from your hand (except that you're not actually doing that, so you can't play units onto quests. I think.).

Thanks! I'm quite curious about the upcoming expansion.

Just another question on necromancy. If the unit dies on its turn and goes to the graveyard, do you have to put it at the bottom of your deck or can you ignore that effect?

You can ignore that effect.

You may now go and re-read the Countess's ability. You may want to put on a bib for the drool first.