If Manaroo has a Weapons Engineer crew and gains 2 target locks, and then gives away her target lock tokens to another friendly ship; does the receiving ship get to keep both target locks?

No.

Without WE a ship can only maintain 1 TL at a time. If it somehow acquires more than that it must discard blue lock tokens down to the legal limit.

Yeah it's the same as when someone like Redline would take the crit from the old deck that ignores your pilot ability. He would have to discard one of his two locks as he no longer has the ability to maintain two at once.

it is still sort of good on Manaroo though, as it gives you more options for which lock the friendly ship keeps. If one lock was on a ship in their range and one was on a ship out of their range, gives you that option to give them the 'good' lock and lose the other.