How does interaction between these two cards work?

1. Assault missiles will deal out cards to all ships in range 1, and then Rex will turn them all up.

2. Assault missiles will deal out cards, but Rex will only change cards of the initial target as others are cards dealt and not damage dealt.

3. Other interaction.

Ok, so Rexler's text:

• After you perform an attack that deals at least 1 Damage card to the defender, you may spend a focus token to flip those cards faceup.

So, the way I read this is it is referencing cards dealt to the defender of the attack, then indicates those cards be flipped up. Since the extra damage cards to other ships are not part of the key word 'Those', they would not be flipped up.

I like the way you think, but I don't think it works in this case.

Number two, though I would say it is more because the other ships are not the defender of his attack

(Real problem with this ship name, especially in mirror matches: so...the defender is the attacker and shoots assault missiles at a tie phantom which splashes damage onto col. Vessels, but the defenders ability doesn't effect the defender because the defender isn't the defender even though the defender damaged the defender by attacking)

You mention twice about assault missiles dealing out cards to the other ships - they don't do that. If they hit they only deal 1 damage to other ships at range 1, if those ships have shields then they just lose shields.

As others have mentioned, rexler's ability only works on the defender.