I will submit my post as soon as I've written this.
Now,
Groin and I were thinking that Ori, Náli, Lóni and Trór would probably be there when Balin is shot.
Foley and
Gwath, you may decide whether Kenan and Frar are there (depends on how well they know Balin). There can be a couple of Balin's NPC friends, too, but we don't have to think about them too much.
Legate, we were thinking that Óin wouldn't be there, but scouting around and he and his companions could then bring the word of the bigger Orc group.
We will try to get Balin's killers killed and his body to Moria in a few posts so that we are all more or less in the same place (except
Boro, who I understand has been making special arrangements with
Groin). But you others don't have to be idle while we write about Balin's death and the fight, of course - you may write about your characters' normal life, it will bring a nice (nice?) contrast with the soon coming news of Balin's death and the approaching Orc army...
And lastly,
Groin,
Boro and
Legate, you need to get this Orc army/scouting/where are Óin and Gror stuff solved, I don't want to get muddled in it because
Groin was the one who had a clear vision about it.

So, basically, we can expect that
Groin will talk about these things with you players and inform me when it's solved.
I guess that's all for now. Feel free to post (and ask questions, many things are open even to me at this phase

).