Thunderhawk without fearless (in the SL battle) would have been destroyed I assume, as per air rules for losing air assaults 'If the aircraft loses the assault it is destroyed'. In this situation ATSKNP would not have saved it, as it was not being hurt by hackdowns, but due to being 0 speed and an aircraft. Fearless does help the thunderhawk stay around longer (as intended by list),
but I think it may be too strong as it removes one of the risks of the air assault.
List would have looked different if knights were WE, as the WE/air section was pretty much maxed (which is why i took a subj, no points for questor). If they had been in WE section I would have had to think carefully (espec at 2k, only 660 allies points to play with) as it would be hard to take a solid formation of them and air assault.
Other lists used against EC were as follows:
Steel legion 2k/7 activations:

RHQ (+hydra) BTS
Inf Coy
Manticores
Shadowsword
Sentinels
Thunderbolts
Warhound pair (had to be a pair to fit in 660pt allies allowance)
Marines 2k/7 activations:

Devastators (+hunter, +SC) BTS
Terminators (+chaplain)
Land Speeders
Predators (all annihilator +hunter)
Thunderhawk (transporting terminators)
Thunderbolts
Warhound
(i do own 'proper' warhounds, honest, 's just they're all in bits!

)