Are you interested in having a dedicated lurker? I haven't looked at any of the other threads thus far, and I think it would be more fun to see this game from one team's perspective than the global one. I promise that I will not try to steal control away from the actual turnplayers, I don't have time to run a PBEM game at the moment.
Thoughts on civ choices... It sounds like the map setup is four separate continents with each team of two on its own continent, separated by small channels of water (not oceans). That suggests to me that naval-oriented civs will play a role but not to the same extent that they did in PBEM4. In terms of religions, there will be 5 religions available in an 8 team game which means that every team should be able to get one without any issue. (There isn't much point to a team trying to claim multiple religions and having them compete against one another.) That means it shouldn't be too hard to get a religion regardless, although getting an early one for some of the key religious tenets could be very valuable.
By and large, my advice would be to avoid getting too cute with the civ picks. Choices like America and India and Egypt are subpar options when everything is on the table. Here are some quick individual thoughts:
* Rome is always a good option. Ignore the early rush with legions and concentrate on fast expansion with the free monuments and ultra-cheap Baths (which are even more amazing now after the big cost reduction to aqueducts).
* Germany and Australia are slow-developing options that could be really strong on a map where there should be little early military pressure from other teams. I'm not sure that Singaboy wants to play Germany a third time though.
* From the downloadable civs, I would take a look at Nubia. I think they're arguably the best of the DLC civs when not playing an early military game: potentially +40% production towards ALL districts with that unique tile improvement, an overpowered UU archer with extra damage and movement, +50% production and +50% experience towards all ranged units for the whole game (get those double and triple promoted archers/crossbows super fast), and bonus production/gold for mines on resources. I'm honestly not sure why no one chose to play them in PBEM6.
* On the second half of the snake pick, I would also seriously think about picking China. I think the civ is great and especially in an early game builder's context where there won't be military pressure from other civs. China is undervalued at Realms Beyond right now because Woden fell apart with them in PBEM2. It's easy to forget that he was running away with the game while playing as China and pretty easily could have snowballed them to a victory (he could have used his science and gold lead to rush to field guns, then do a mass upgrade of crossbows and defeat one of his neighbors - it's how I would have played it). China gets the extra charge on builders from the start of the game (super nice: Craftsmanship boost plus a free forest chop / stone harvest on your first builder) and the 60% science/culture from boosts. Even better, China gets a guaranteed Stonehenge/Pyramids/Colosseum/Petra because no one else will even make an attempt to build them in a game with China around. China's biggest weakness is defending against a Classical or Medieval era attack because China wants to be in builder mode at that time. If you can remove that with a Continents setup, they become one of the best options.
* Civs I don't like: Aztecs (Eagle Warriors can't exert early pressure), Macedon (similar reason: not a rush map and that's all they can do), Greece/Gorgo (she will be overvalued by the RB community and the Wildcard slot's ability to take the first Great General isn't as useful here), Scythia/Sumeria (are they unbanned for this game?) The shared allied rewards from Sumeria aren't enough to overcome the inability of the war carts to hit anyone early. Also as said before, avoid generally weak civs like America, Brazil, Egypt, India, Spain, etc.
Hope that helps. Good luck!
