I think Scarf/Specs Heatran should be recommended as a teammate for NP+BP Celebi because Celebi can NP on the turn they go into Skarmory/Ferrothorn/Scizor and then you can BP the +2 onto ScarfTran, which can then clean up very well mid-late game or BP it to SpecsTran which then has a terrifyingly powerful Overheat and Fire Blast.
+2 252+ SpA Choice Specs Heatran Overheat vs. 252 HP / 4 SpD Eviolite Chansey: 445-525 (63.2 - 74.5%) -- guaranteed 2HKO
Fire Blast 2HKOs Chansey, that calc is just a testament of the power.