Red Five is out. Attach the Luke Skywakler Pilot enhancement. Can I attach Old Ben's Spirit onto Luke? If so, can it save Red Five or only Luke after he's ejected from the vehicle? And if it's the latter, does that mean I have to wait until he ejects to give him Ben's Spirit?

I think I just confused myself.

I believe an attached pilot becomes an enhancement and loses its status as a unit.

So Ben's Spirit cannot be attached to Luke while he's piloting. This is my take on it.

Yep, when a pilot is acting as an enhancement it is not a unit.