Can Han Solo do his rerolls multiple times? Han Solo Pilot, Luke Skywalker /Gunner Crew, Cluster Missiles:

Declare attack, use Cluster, 1st attack, roll. Reroll using Han. Miss. 2nd attack, roll. Reroll using Han. Miss. Luke/Gunner triggers, attack with Primary weapon. Roll. Reroll with Han. That's 3 rerolls during 1 declare attack, right?

Yes you can Han’s ability more than once per TURN, but not more than once per attack. You got the right idea. All those are separate attacks, so reroll away.

Yup, its once per shot, but it ends with Luke/Gunner