3/5 of these are obtainable with little to zero effort if you have catacombs. 30 combo and 2000 kills are as simple as you and your partner both camping under the fan of death. The 30 combo is pretty much mandatory in this situation and the only things you have to worry about are the lanterns and the acid zombies. Take care of those before they stunlock you in acid or flames and you're good. Should get a few hundred per round without any real effort going into it.
Win while dieing is also done with next to no effort in this stage. Just run into the spike trap, instant fatal. whoever is giving the other person the achievement, crawl back into it while dieing.