There are many options at 2 cmc. I assumed it was a curve thing, where you need some at 1 cmc to replace Astrolabe (also not an enchant). Unfortunately there isn't much at 1.
Abundant Growth is off color.
Remora has always been mediocre in Legacy compared to Vintage. You could try it out, but it's bad tempo.
Sarcomancy seems risky in a slow control deck with no other zombies. It's questionable whether a 2/2 token is worth a full card in this shell too, though it does help slow down aggressive starts. Any positive results with it?
Maybe it's better to just play
Preordain in that slot. Less synergy with the engines, but it will lead to better curve outs and better overall value for 1 mana.