Aang would be happy to go tackle Ales due to his comfort with heights and air and stuff. If whatever equipment permits regains is in Aquares Ixen, Aang would go along.
Nanami could be talked along with anyone; she's more inclined to go with people she knows.
Tazendra does want to find out what's in the mines. As for which fiend, she's game for whoever needs a Crystal Knight. She has no personal stake or elemental affinity. (She does like Deadpool for inexplicable reasons, so would rather face someone else.)
Also, if someone wants custody of Momo, that would be great.
Aang/Nanami/Tazendra
Nanami could be talked along with anyone; she's more inclined to go with people she knows.
Tazendra does want to find out what's in the mines. As for which fiend, she's game for whoever needs a Crystal Knight. She has no personal stake or elemental affinity. (She does like Deadpool for inexplicable reasons, so would rather face someone else.)
Also, if someone wants custody of Momo, that would be great.