First things first there is a monkey wearing a nappy(or daiper if you want to get american) which will win the next gen war for Kojima productions.
Dreben is a new character who did the narration for the beauty and the beast trailer at GC. HE's an arms dealer Who hopefullly has at least one FN P90 for spares. The Monkey hangs out with him. DOn't question metal gear. It's just as smart and thought provoking as the cardboard box.
Dreben's seems to be partly for humor and also for plot. kinda like jar jar binks but better.
Also olga's Daughter stars in the game, named "Sonny" or maybe "Sunny" but regardless i assume she'll be hanging out wih Raiden judging by the fact you can see him holding her. But Otacon's going to be kind of her caretaker.
Also i hate to backtrack but if you watch the HD trailer for when OCelot leaves the balcony after saying "Activate it" YOu can see a figure dressed similarly, yet differently to Naomi with their face covered deliberatly by Ocelots Shoulder.
Also on top of the already all female beauty and the beast unit new female seeming Haven soldiers are in, the games obligtory ninja's. MAking the connection from OUter Heaven to Haven you don't need my help to join the dots there. OUter heavenhas one named PMC which is the preying mantis, based in the UK w00t!
Meryls hair looks less like a plastic action figure too.
Also METAL GEAR VS METAL GEAR literally and not in a twin snake way either, REX vs RAY.
And also an armoured truck, probably containing snake and definatly dreben judging by the monkey, runs down some gekkous. MGS4 will have a trial MGO2 though. Bit of a control change but otherwise it's definatly as close to perfect as it will be getting.
Also MGO2 info but you've probably seen it already

SOP is NOT Standard Operating Proceedure
But there IS an MPO+ trailer on the event site tomorow, maybe not on english