Perhaps a bit lawyerie, but:

• Deadeye: "When an attack instructs you to spend a target lock, you may spend a focus token instead."
• Cruise Missiles: "Attack (Target Lock): Discard this card to perform this attack. You may roll additional attack dice equal to the speed of the maneuver you performed this round, to a maximum of 4 additional dice."

I think we can that the rules as intended is that one can use a focus token to fire a Torp/Missile. However, the Deadeye card SAYS "spend", and the missile card simply says you need to have one. It seems to me that deadeye does not work on ordnance that does not specifically says "spend" (cruise, harpoon and homing missiles).

Thoughts?

You're ignoring the entire first half of Deadeye

In this case, Deadeye would require you to have a focus to fire the cruise missiles. Nothing more. Just think of it as Deadeye 'cutting and pasting' TL with Focus on the ordnance card.

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.

It helps to quote the entire card...

But quoting only half the card makes for a discussion. Quoting the full text shows you don't even need a discussion.

Piling on...