This isn't AW, just we have to conquer the world. But AW civ traits are good for this "variant."
I'll have a "maybe" roster for those not sure and a "sidelines" roster for subs to fill in.
I vote Japan, good for early war as we have cheap barraks' and temples, and good Middle Age warrer because of the samurai. Militaristic is good for lots of leaders, lots of armies.
One other thing, no GL, we can capture it if necessary. But we'll be conquering a lot, and will be able to research ourselves very fast. City spacing should be 2 tiles INBETWEEN cities. This makes lots of cities with enough tiles to get to size 7, for tons of free unit support.
First to go takes 20 turns, then 10, then 8 in middle ages, 5 industrial and 4 modern. I guarantee we'll be fighting till then, as we'll be facing 15 opponents. Since this is a huge map, turns will start to take forever, so the more turns you have to take, the more overwhelming it is. In the middle ages already, you'll probably have a 3 minute wait inbetween turns. Modern, maybe 20 minutes. That's just an estimate as I've never been in modern times on huge, cause it's very boring to get there!