(in order of appearance, sort of)
(not that this will help any)

Silent and grave, occasionally uttering "sage" wisdom.
Master of MUD clients and stuff.
He burns things and is the eldest of the SPRoW people. Angry when wet.
Pica pica. We don't know what to make of him. Token yank.
Mariusz talks a lot; about what, we don't know. Also enjoys opera. A different version of Gaz. Knows many things and is grumpy.
Tinuviel is a fairy with a child. I think.
Twiglet is Gareth's soulmate and remains as inane as he is insane.
A stranger from the north. Dazzles everyone with his knowledge of things. Also sulks. She is a young human being with much promise, largely squandered spodding. Master hovercraft mechanic.