If I kill a Baited Hook target on reaction, does it still fire with the target's might?

No, the ability will not function as you intended. If the targeted unit is removed (killed, bounced, or otherwise leaves the board) in response to your activation of Baited Hook, it cannot be "killed" by the ability's instruction.

According to Rule 359.3.e.12 and consistent RiftJudge FAQ (#10345, #1590, #9430):

1. Kill Instruction Fails: Because the targeted unit is no longer on the board to be killed, the instruction "Kill a friendly unit" cannot be followed.
2. Null Might: Since no unit was actually killed, there is no "killed unit" to reference. Consequently, any reference to the killed unit's Might value returns null.
3. Resolution: Baited Hook will still resolve as much as possible—you will look at the top 5 cards of your main deck—but because you cannot satisfy the condition of finding a unit with "Might up to 1 more than [a null value]," you will be unable to play any unit. You will then recycle the 5 cards.

Sequence Summary:

1. Activation: You activate Baited Hook and target a friendly unit.
2. Reaction: Your opponent plays a card to remove/kill that unit.
3. Resolution: Baited Hook resolves. The "kill" instruction fails. The ability references the "killed unit's Might," finds null, and therefore cannot complete the search/play portion of the effect. You conclude by recycling the top 5 cards of your deck.