Well, you have to have 4 specific bounty hunters to acquire the OG Falcon ship. Those are:
Boba
Bossk
Cad Bane
IG-88
For Chewbacca, you'll need Dengar (which you're already working on) to get to 7*, but you can probably get Chewie at 5* and maybe even 6* without Dengar, so he can lag a bit behind the others if necessary.
For every purpose other than the Falcon event (where you have no alternative), you'll probably want to replace IG-88. So with Dengar, you then only have 4. But lucky for you, Jango is on the same node as the Hound's Tooth ship.
Since you have to farm Hound's Tooth, you effectively get Jango for free, and Jango's a great BH.
So your initial BH lineup is probably going to be Boba, Bossk, Cad Bane, Dengar, & Jango, but all the BH are decent. Embo and Aurra are pretty great, but Embo is a long farm and Aurra is in the Cantina, where you're going to have other priorities. The last two are Greedo and Zam. I really like Zam against enemy squads that don't have any Tenacity bonuses, but she only really works like she's supposed to when you can blanket the enemy in Thermal Detonators, so if the enemy does have Tenacity bonuses she's really not a good toon to use. Greedo is fine, but not special except in certain limited situations.
So it's up to you, you have lots of options, but if I were just starting out, I'd probably stick with that initial BH lineup for a while. By the time it's a good idea to move on to a different BH lineup, I'm sure you'll have your own ideas about whom to farm & gear next to fit your play style and preferences (and it's always possible that they'll release a new one or two by then), so I won't try to tell you what to do.
In fact, let me take a moment to say that even though I'm telling you what I think is a good idea, if there's ever a difference choice that increases the fun you are having, choose that.
It's a game. Always choose the most fun option. Usually it helps you have more fun to farm and gear teams that work together well and help you progress through the game faster, because that means you get to play more events sooner or be more successful at the events that you do play (like TB, where you can start a battle with a single qualifying toon, so technically you 'can' play, but that doesn't mean getting instantly blown up is going to be fun for you). But if there's ever a time where you think that getting the absolute max advantage is making the game less fun for you, stop worrying about the max advantage and choose the thing that's good enough and gives you back your fun.
here endeth the lesson.