First of all, I think it's a buttery nipple, but I could be wrong.
I have a small piece of advice with respect to your start point.
If you want the game to have a small number of players, unless they are all invited players you know personally, do not start with a briefing.
I'm speaking from experience having tried to run a similar game three times in the past. If you start with a briefing you will end with the briefing as all the players drop out one by one. Start with the action. Do the briefing OOC and start with a raid or something.
The only reason not to do this is if the game is to be sandbox and you allow the players to create their own action. If you do this, however, you will need to use a system, and I can't help you with that!
If you intend to have open recruitment, and want a lot of players, be prepared for disappointment, too. In my experience if you get ten players interested, you will get six actually play. If your idea presentation is good and the idea is interesting, you may get twenty or thirty interested. You will get ten to fifteen actual players out of that!
You need to have a way to get rid of drop-outs and bring in newcomers, in the middle of the action.
Thufir's question 2 is the key one regarding freeform or system.
And finally, totally irrelevant to the above...
A long slow comfortable screw against a wall.
This is a cocktail of cocktails.
1 shot Sloe Gin
1 shot Southern Comfort
1 shot Vodka
1 shot Galliano
To top Orange Juice
The name comes from:
Long being either a long drink (as opposed to a short) or possibly that the drink is a variant on a Long Island Iced Tea.
Slow a phonetic variant of Sloe which is a berry that grows wild in the UK and is used to make Sloe Gin
Comfortable, from Southern Comfort
Screw from Screwdriver, which is Vodka and Orange Juice
Wall from Harvey Wallbanger which is a screwdriver with Galliano added.
Yep, I'm a mine of trivia!
I have to say i sounds awful