Well,
EZdrummer 2 is actually running 24 bit with newer EZX:s. Older EZX:s, made for EZdrummer 1 are 16 bit.
A newer EZX is also loaded as 24 bit in Superior 2 but you have the option to load it as 16 bit, as you have with SDX:s.
I am wondering if you are confusing the MIDI files with Audio, since you ask about using the Avatar drums from Superior?
Superior 2 SDX:s cannot be loaded in EZdrummer 2 but of course you can use the Superior 2 SDX MIDI files in EZdrummer 2.
If you are working in 24 bit in Logic it only matters what the Bounce is intended for; generally a Master would be @ 16 bit, pre-Masters @ 24 bit as well as Stems Bouncing.
BR,
John