Sand, gravel, and other earthworks

I think you don't need to have the breakdown detailed for each federal state. Certain costs vary from property to property and from house to house (length of pipe routes, soil conditions, connection costs depending on association statutes, etc.), some, e.g. gas connection, are only partially needed, real estate transfer tax depends on the property value (partly also on the house price), notary costs depend on the property value and the amount of financing. Therefore, a breakdown is of little use to you. I think you're best off if you factor in Epi's average value. For Mecklenburg-Western Pomerania, you certainly don't have to aim for the highest range, but better to plan too much than too little.