So there's four players playing through the core campaign at the moment: me as the Imperial and three of my friends as four rebels. Each of them have their own character and then they share control of Gideon.

The rebel characters goes as such in the campaign sets:
Core - 6
Twin Shadows - 2
Hoth - 3
Besbin - 2
Jabba's - 3

If we want to have four new characters for every campaign, we'd run out of them by the time we reach Hoth (Twin Shadows would use the two "extras" from the core set). If we played the expansions using only three per campaign, we'd be fine all the way thru Jabba's in the sense of having fresh heroes fo each campaign.

But what I've been reading from this forum, is that the game balance suffers if there are less than four rebel characters. Is this really so bad if we had just three? Experiences?

Also, I'd really like to have side missions in between the Twin Shadows mini campaign story missions. Has anyone tried to reconfigure the campaign reward- and threat-wise to achieve this?

Using 4 heroes is better. The missions will be less swingy.

Each hero can be developed in a few direction depending on what the other heroes are and thus what the group needs. Are you sure you don't want to try that? (For example Diala can be full support, your high-damage melee fighter, or your area-effect damager with Way of the Sarlacc. Mak can be sniper with high single-target damage, support for picking up crates with Expertise and Supply Network, and objective runner due to having good tech test. And so on.)

For Twin Shadows and Bespin Gambit you should probably use the heroes that come with them, then fill in with others to create a balanced group.

If you want to make the minicampaigns a little longer, see my extended Twin Shadows minicampaign (7 missions) from:

https://www.boardgamegeek.com/thread/1507945/rise-and-fall-twin-shadows-swia024-finished-201607

The minor problem was that the rebels encountered a bit too many green side missions, so you want to keep an eye on that.

In my Bespin Gambit minicampaign we started with an additional hand-picked intro mission, and apart from using too low threat level (2 instead of 3) it was quite good and I think I managed to tie it in pretty well to the campaign. We'll be playing the mission from the ISB Infiltrator pack like instructed, then possibly one hand-picked side mission (Lando's pack).

https://www.boardgamegeek.com/thread/1601278/cloud-city-crackdown-swia033/page/1

Looks great and thanks for the 4 heroes advice!

I think I'll force them to use Mak and Diala for Twin Shadows, because those two are the ones that my friends didn't pick for the core campaign. And on Hoth they just have to re-use one hero.

For the Twin campaign you did not include red side missions (besides the story ones for Saska and Biv) from the core set?

Kiitos!

In Twin Shadows and Bespin Gambit the respective heroes' missions are used as two of the story missions. So allowing red side missions would've changed which ones were available depending on which heroes are selected.

The red side missions are usually quite specific, so they may not fit that well into the story of the minicampaign. I did not really worry about that with Twin Shadows, but with Bespin Gambit I actually chose the intro so that it fits the campaign and does not have too unbalanced rewards. Once the rebels have selected their heroes you can make the decision whether the hero missions can be included.

Twin Shadows and Bespin are both only 4 missions. You're not really using the heroes very long there, just re-use heroes you've already used for them.

For Twin Shadows and Bespin Gambit you should probably use the heroes that come with them, then fill in with others to create a balanced group.

Bespin really feels like it was made specifically to screw the heroes that came with it. Taking Davith's lightsaber off the bat leaves him pretty incapable of dealing with the cameras, and completely screwed against the Bespin class deck which can force range requirements against meleers, better buying a Vibro Sword than spending 3XP. Taking Murn's threat reducer for Lando is wasted XP in the final mission as you aren't allowed to take any allies.

Vibrosword and Falling Leaf for Davith seems to be working well against Stealth in the Bespin campaign this far. (Rebels should spend their XP for actually useful skills rather than weapons. Use XP for weapons only if you absolutely need to.) (And the rebels had no trouble with the cams with their ranged attacks and Lando taking out two with his elite attribute test.)

However, unless you use only 2 heroes, it would not matter that much what each of them can do. The group matters.

Yeah, I'd add that if you went Heroic (the +3 health and the sharing of 1 additional activation token) isn't as broken either as Legendary (+10 health and each hero gets 2 activation tokens). So it's manageable with 3 heroes/players if you wanted.

~D

You could chose 3 heroes and then "a hero" i.e. a unique Rebel hero to be played by a 4th system. Even if you wanted to go with normal rules you could double that uniques hit points and allow them to make two attacks per turn if they don't move. They wouldn't upgrade or interact, but it is something.

As others have said re using a hero isn't that big of a deal considering that they have multiple builds. Whatever way they went the first time, tell them to try going the other way the second time. My Rebels are the opposite, they always want to play the same characters now that they have figured out which ones are best and how their builds mesh well together. Be thankful you aren't continuously facing off against Diala/Fenn/Gideon/XXXX every campaign I told them if they play any those three when we start our new Hoth campaign I am running Subversive Tactics, I think they will be picking new heroes..