Maybe someone can help me out here.

tldr; Read #1, if this is wrong, then disregard wall of text.

1. In regards to the card Deadeye, does the text: You may treat the "Attack [Target Lock]" header as "Attack [Focus]"..." mean that you may use a secondary weapon without having to target lock? As in, I take a focus action, with no target locks, and then use a missile/torpedo on any enemy of my choosing? A possible interesting tactic for making your enemy guess your real target that I ASSUME was the intent of this card, but I could be wrong.

2. If the above is true, then I'm thinking there is an interesting interaction with homing missile that I haven't seen brought up yet...

Homing missile does not require you to spend your target lock in order to perform your attack. So, if Deadeye lets you use your missiles/torps on any enemy with just a focus token and no target lock (as I discuss in the above), homing missile will not spend your focus token, leaving it available for possible use...

The major question is, will you be able to use this focus token to flip eyes on your current homing missile attack? This is less likely since I would ASSUME you cannot spend your target lock on a homing missile attack, though I have never seen anyone question it, but could just be a simple rule I missed reading...

3. In another case that I assume to be 100% true, let's say you have a previous target lock on an enemy, and you perform a focus action. You use Deadeye's ability ( You may treat the "Attack [Target Lock]" header as "Attack [Focus]"..." ) to perform a Homing missile(or any missile) attack on the target locked enemy, stating that you are using your focus token to declare the attack. I assume you would then be able to spend your target lock to re-roll die, since the focus is being used to start the missile attack. Just pointing this one out in case no one thought of it...

Here are both homing missile and Deadeye full text for use...

Deadeye (1)

You may treat the "Attack [Target Lock]" header as "Attack [Focus]". When an attack instructs you to spend a target lock, you may spend a focus token instead.

Homing Missiles (5)
Attack [Target Lock]: Discard this card to perform this attack. The defender cannot spend evade tokens during this attack. Attack: 4. Range 2-3.

Answers, comments, and concerns welcome.

I could just be late to the party on this one...I don't see anything in the FAQ. I will consult the rule book next.

The point of homing missile is that it leaves the target lock there so that you CAN spend said target lock on the attack (in addition to the bit about evades). Yes, Deadeye presumably allows you to do the same with focus. Yes, if you had a TL you could do that as well. One of the most powerful offensive combos in this game is F/TL (Focus/Target Lock) through stuff like PTL and synergy token pass or free action ships. F/TL Homing Missiles is certainly a great strike but keep in mind that it is only one strike. One strike can matter in this game, and F/TL gives it its best chance to matter.

Yes, you are bit late to the party, since those questions have been already discussed to death, but in short:

1. Homing Missile + Deadeye: You can activate the missile only with your focus token. Activating the missile doesn't spend the focus token.

2. Since you didn't spend the focus token to activate Homing Missile with deadeye, you can use the same focus token to convert Homing missile's eyes results to hits.

3. Deadeye + Target lock: You can use either your TL or your focus token to activate the missile, and use the other to modify the damage roll. In the case of Homing missile, since you don't spend what you use to activate the missile, you can use both to modify your roll. (I assume your are attacking your Locked target)

The main advantage of deadeye is that you can choose any target in your arc of fire to be the target of your missile (Target Lock restricts your target selection to your locked ship). Also, note that it lets you use your missile on targets that were originally outside range 3 during your perform action step.

That's good information, I always assumed the focus token got spent for some reason. Now silly question time: Does Deadeye therefore allow you to fire a missile at a ship that would otherwise be immune to being "Target Locked" due to Captain Kagi being in range? As his rule says you must Target Lock him, does the fact you are using a focus token and not a Target Lock to select your missile target get around his ability?

Correct, you also get around Kagi by using deadeye.

Thanks for clarifying. Research is hard, asking questions is easy.