What Recipes does this replace in Krastorio 2?
It replaces up to 3 recipes, Biter Research Data, Steel, and the Coke recipe itself.

Is steel still rationally correct?
Yes, it is. It requires 10 iron plates, so the 2:1 Krastorio 2 recipe is maintained, just without coke.

What is the "Easier Coke Recipe"
If you enable this coke will no longer require wood. Although this option is useless if you have the other two enabled, since the new coke recipe will be used for nothing.