We have just finished a build for ADE that is designed to run properly against Prepar3D.
This means that if you have P3D then it will appear as an option in the Version Selector. Each FS version in ADE is setup in a separate compartment. So the P3D version (ADEP) should not cross over at all with FSX. It has it's own databases (from P3D) and uses the P3D SDK for the compilers. It should connect to P3D etc etc.
More IMPORTANT detail here