You can sell the air for about 50k-70k and the fire for upwards of 20e. Please don't mind the above.
I've bought a lot of celestial staves, 20/20 and especially 20/10 so I know precisely what a fire celestial 20/10 can do when there is a market for it.
I respectfully disagree with both of the posts above me. 20/10 can be a real pain to sell, it will take time to find buyers at these prices, but I'd say:
~50k for the Air
~75-80k for the Fire
~75-80k for the Divine Favor
These are the high end in my opinions. I have sold quite a few Celestial 20/10's in my day.