[Daynarr]

Haven't tried Death 9 pretender yet but it sounds like a good choice. I think you are right; Breath of Winter could be best way to kill of CM’s and make them undead.
I think RM is worse choice since you get so many special holy troops waiting for right blessing. Not to mention that your Celestial Masters (and Masters of Five Elements if you use S&A) can find most of sites by themselves.
Fire or water 9 pretenders are good, and nature 9 is not bad either for Celestial Soldiers. Earth would do more good to Celestial Masters but big question is do you want to invest in them if you face Arco/Pythum, which can kill them in duels. I guess Earth choice would depend on game settings and opponents. The only choice that seems like a waste on them seems air since your sacred troops don’t need it or simply can cast it themselves.