You should be able to load both of these cards in an open slot. You just need power to the card. Get a backup of the existing card(s) and build that back into the new card. Once you have the cards ready, I would remove the old cards from the security domain, and then undeploy the applications and then replace the cards with the new ones, redeploy the applications and then join the security domain.
I am assuming that you have the co-res setup on the cpmg and then a follower signaling server on the cpdc? You are right, not much documentation on these cards.