Yes red means dead. Every eliminated member of the Org. had the red color along with a destroyed portal. The blue ones were doors to the live ones, duh. Roxas's door was shattered because he is in Sora, but still alive. A shattered door means you can't reach them, and blue means they are alive.
Forget about Zexion, he died, get over it. Maybe he didn't even have a weapon, he relied on his wits and didn't like dirtying his hands. We shouldn't care what his weapon is, because if we do, he'd still be dead, so you'd fight a metal weapon that lies on the grounds and doesn't move.
His weapon wouldn't be a keyblade either, because Roxas is the nobody to control the keyblade, another nobody to wield the keyblade would be stupid, and throw off the storyline.
Done.