The more bodies in combat the merrier, as far as I'm concerned. The more of us there are, the more mileage I get out of my rituals.
Zook's followers will be staying home minding the store, I believe, so that's 8 spare insignia if you need them.
And most of Cornelia's followers will probably never see combat (although most of them are being built for the possibility of being selected for missions), so we'll probably never run out of insignias.
I did a little shuffling around on the NPC list. Natali is 2nd level, Kossor is 1st. Do you know any classes that are better at going undetected at level 1 than rogue? She's not ever supposed to see actual combat. In fact, we shouldn't really have a reason know she's in the room, most of the time.
The other characters appearing on Cornelia's battle roster are Winthrop, Tink, Revan the shield guardian, and Uru the kobold spellshaper.
Cornelia is your healer. She should never get into melee, but if she does, she can suck 17 hit points out of her attacker and give it to herself and/or others every round. Six times per day, if you're down on hp and need them, you can spend a standard action to ask her to heal you, and she can give them to you for 3 hp per 1 pp as a free action. You don't need to wait for her turn to get healed. If you're down by 13 hp and ask for her healing, and she gives you 15 hp, you can send the 2 you don't need to another character. She'll most likely get the PCs started in combat with
battlesense. She can do a couple other things, too. You might appreciate the fact that she can manifest
vigor on you, even though it's normally a personal power.
Revan's purpose is to stop Cornelia from taking damage. He won't be doing much of anything, ever. Except getting in the way of characters trying to harm his charge. Cornelia might second him to another NPC in need of short-term cover and protection.
Uru is riding Tink (your argument is invalid). His job is to use his arcane formulae to be a damn frustrating bastard to our enemies on command, and otherwise to wait for something to hurt Tink so he can peg him with 1d8 fire damage as a quick but small heal.
Tink's job is to stand there and look ugly, and to provide all of his adjacent allies with a +4 bonus on AC and Ref saves. Additionally, if anything gets close enough to him, he'll unleash a full attack of 2d6+5 and 2d6+5 with his slam attacks, with no penalty on the iterative attack.
The standard battle arrangement for Cornelia's company looks like this:
C = Cornelia
W = Winthrop
R = Revan
T = Tink
u = Uru
n = Natali
The top side is the direction Cornelia is facing. Why aren't Natali and Uru's initials capitalized? Because they're not supposed to be in direct combat with other characters. As you can see, Tink has a couple of slots around him that are still open. Feel free to assign a character to one of those slots to gain his protective bonuses, should you desire it. Be aware that he can't move more than 20 feet per round on his own, and even then he needs a swift action to activate his boots to get that going. Without the bonus from his boots, he's stuck with 10 feet per round.
Something important about Cornelia: currently, her worldthought network can only reach out to a 40 foot radius around her, and her steal health attack is melee-only and does only 17 damage. At the next level, her network will improve to 170 feet, and she'll be able to steal health from up to 30 feet away for 19 damage. Also, she'll be able to trade in her soulbound gauntlets at that point for... probably... a better periapt of wisdom, so her steal health may bump up to 20 damage.
Sorry if she's lagging behind a little right now. It can't be helped.
Edit: Speaking of teamwork, there's a kaorti cocoon item that Uru could really benefit from during round that he's not being actively engaged. Tink could use the cocoon as a sort of backpack which Uru hides inside until he's needed (and should be no worse for initiative, as Cornelia can direct him via telepathy). Is that something you can make?