If lieutenant leheuse has a lock on an enemy ship and is equipped with FCS, can he use FCS to reroll one of his attack dice, and then subsequently decide to spend another ship’s lock to reroll the other attack dice? (Of course one cannot reroll the same die twice)

RAI I believe this is against the restriction on FCS but RAW it works because FCS only stops you spending YOUR target lock while leheuse can spend another friendly ship’s lock

from my own analysis this is mostly irrelevant in a 3 dice attack but supposing a 4 dice attack things get spicy as you may want to try to turn a blank into a focus before spending a lock on the rest