Should I farm boba or Jawa next in cantina shipments?

Regular Jawa? Or Jawa Scavenger?

If you're going for regular Jawa you can do both at once. Jawa with your Cantina energy and Boba Fett with your Cantina tokens. If you're going for Jawa Scavenger, then I would have to suggest Boba Fett instead.

Boba Fett's a strong character that will serve you well in a lot of phases of the game--ships, heists, arena, advancing Dark Side boards, mod challenges, Galactic War, raids. Jawa Scavenger is a really good character, I can't stress that enough, but he's more narrow in scope, being good at raids mostly. Also, Jawa Scavenger gets stronger the more Jawas you have in your squad, so you're going to need to work on a couple other characters to get use from him.

Get the Scavenger eventually, but don't stress it now.

Definitely Boba! There have been a few times where he was the only one left on my team, and I still managed to pull off a win.