I'm assuming that based on the rules from page 18, you can't use the Han Solo crew card in your squad if you are also using the Han Solo ship card, as they share the same unique name?

You assume correctly.

Correct. Although your head may explode if you attempt this because our puny human intellect cannot possibly fathom the coolness that would be... double Han Solos. (Not even the Dos Equis guy could handle this)