Ok, I know the mixed team format isn't officially supported, but I'm curious as to how you guys would resolve the following:

Dutch Vander's ability says "after acquiring a target lock, choose another friendly ship at range 1-2, that ship may immediately acquire a target lock". My other ship is a normal TIE fighter that doesn't have the target lock action, what happens now?

A Tie hasn't got the equipment or ability to target lock, so it can't. I guess the background for this effect is for one ship to transmit the data to another ships computer.

I disagree - Dutch says that a friendly ship takes a target lock, so I would let the TIE do it.

It doesn't say "give a friendly ship a target lock if they have the right icon in their action bar".

Play it however you want. As you said, you aren't playing by the rules already once you start mixing squads.

I've been tempted to try mixing squads myself, though. I would probably say that you can't get a target lock if you aren't capable of it. (If it's not a possible choice in your action bar) But you do what you want, as long as your opponent agrees to the rules, it's fair. I don't think it breaks the game if you do give them any more than mixing squads already does.