@Old_Ben12345
Yes, it matters. Changing the order can impact who is targeted by the enemy AI with certain attacks, etc.
But you can't really control those things. You don't know before the battle which order would be most advantageous.
EXCEPT in this one area: when a mass assist is called (like with General Kenobi, or JKR, or any Geo under a Brood Alpha lead), the order in which the assists are called matters. Now, every source I've seen before @HK666 just above you has said that it's the order in which the mass assist is called is just the squad order.
So if you want Ahsoka or ShaakTi to assist first in order to dispel protections, then you put them in the #2 spot. Padme or JKR or whomever will actually be called first, but you can't help that. At least for the rest of your squad you'll be able to deal damage and inflict debuffs without worrying about tenacityUP or ProtectionUP or that Assault Battle special buff "Overcharge" or whatever else.
Since Geos call mass assists all the time, it's especially important for them. You want defensive buffs dispelled first (and Sun Fac does that for you, so put him #2) and you want TenacityDOWN before trying to land any debuffs (so Soldier before Poggle). Spy just needs to go after Sun Fac so he's not hitting while they still have bonus protection or defense up. But Soldier's TenacityDOWN doesn't matter to spy, since Spy doesn't inflict any debuffs on basic.
So you stick Brood Alpha first, Sun Fac second, and of the remainder, you need to make sure Soldier comes before Poggle.
Likewise, if you're going to be using a Jedi Revan, or Commander Cody or GK mass assist, you want to think about which order would be most advantageous, then put your toons in that order when assembling your squad.
If you have saved squads, make sure the saved version is in the order you want so that you don't have to reshuffle the squad every time.
Now, maybe JK666 is right, and this doesn't work b/c order is determined by animation length. Again, that's not how I understand things to happen, but even if it's true, putting your squad in this order wouldn't hurt. It just wouldn't help either.
it's hard for me to confirm by eye that the order really is what I think it should be, but I'll try to slow things down and take a look to make sure. In any case, it won't hurt, and from everything I've seen, it will help ... but the help I suppose isn't guaranteed.