If you could kill off one of the scions...

[Balipu]

Maybe all of them.
I know, only one. Okay:
Not Y'shtola. I wouldn't make Matoya suffer.
F'lhamin served her purpose so she might not make it.
I however have no problem with her around. Sure she is useless but is not irritating.
Let's see:
I like the banter between Yda and Papalimo and Thancred's constant womanizing.
Alphinaud grew on me. He likes to get things done and he matured a lot. I always liked her sister.

So did I answer the question?

[Balipu]

Diplomacy, logistics, leadership, sexyness etc.

Diplomacy is mostly done by Alphinaud. Actually scratch mostly. It IS done by Alphinaud. Logistics is mostly Tataru but sometimes Urianger and Alphinaud. Leadership: What leadership? Asking me to talk to her mother? Again Alphinaud lead the small group of loyal Crystal Braves. And then there is Yugiri who mostly works from behind the scenes but leads Dozens of ninjas who locate Garlean spies and track crystal braves. She also pretty much lead the rescue mission when we got Raubahn back. Minfilia is only there to look pretty but even in that she is outclassed by every other female character who isn't Matoya. She just has big tits.

[TheCadian]

Papalymo.

Lallafel in a general sense get on my nerves for those stupid over the top actions and reactions they make. This one not only looks like a punk but acts like one as well.

He dies. The rest can live.

[Fevelle]

Thancred. I dislike Thancred as much as I dislike Uldah.

[Grayve]

Tataru would get my vote if I had to pick one.

Love Minfilia.

[AskaRay]

I want none of them to die but I will sacrifice them all in a heartbeat to protect Alphinaud.

So

[BlaiseArath]

Thancred. I dislike Thancred as much as I dislike Uldah.

confirmed for never being my friend

[T2teddy]

I'm going with Tataru, mostly because in the quests leading up to the banquet, her behavior [odd smiles and waving, backwards glances with a frown or strange smirk].

I am none to sure that IS Tataru any more.

[Verdan]

Myself.

They've been through enough.
I'm not surprised to see the bitter hate towards Minfilia, but I think it's unfortunate. Minfilia's just written weird, they don't seem to know how to make her compelling. She's a person with a rare gift trying to fill big shoes, that's a great character. But they never write her in a way that makes us get what she's going through, except for tiny bits at the very end of 2.4-55. I think a lot of the resentment people carry towards her is because of that, and that you hear and see the most of her during the "pray return to the Waking Sands" era of the game.

[Naria]

Tataru and Alphinaud grew on me quite a bit during 3.0's MSQ. I don't actively want her dead but if I could trade Minfillia to get Hauchefant back I would in a heartbeat (or even Noraxia). Minfilla really does seem a pointless character as every role she nominally has is actually being performed by another member of the Scions. It is a shame because I agree with Verdan that her character set-up has a lot of potential.