I think you would need to install Orion and NCM onto the new box (with license resets) and then point them to the previous SQL DB- Then install the HSE on the old server.
My scenario would be:
1) Move the database to the new separate server (first down time for Orion/NCM)
2) Move Orion to the new server (Second down time for Orion)
3) Move NCM to the new server (Second down time for NCM)
4) Rebuild the Old server and install the HSE (Should not require a Third Orion down time).