Homebrew 1v1 Scenario - What would be the best civs?

So, I'm going to start trying out a sort of unorthodox homebrew game with a friend of mine. We've played so much we usually try to shake things up, and this is just another instance of that. What I'd like to do is get people's thoughts on what the best civilizations would be, and what civs people would prefer to choose if they played a game like this.

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Of course, this means I have to explain the game itself. Which may take a little while, so I hope that you stick with me so that I can get some good ideas for what civs I might want to consider.

The way this game works is as follows: The map is going to be a Giant water map. From the farthest north to the farthest south there will be an even arrangement of 9 plots of land. One player's "Capital" will be the Southernmost plot, and the other's will be the Northernmost one. Each player will have a modest set of identical starting resources with which to build on the next three plots past their capital. Leaving the middle plot blank. (In short, both players start by owning four of the nine plots. And while we have the same resources, our choice in what to build and where will have a big effect.)

Additionally, on the East and West corners of the map there will be a set amount of villagers and a basically endless supply of resources to gather. The villagers will be trapped inside a gate owned by the enemy, and towers will be guarding the resources. We will ally one another (with a computer with no alliance to keep the game running) which will allow our villagers to get to their respective resources. 15 minutes we will each have to divide up our villagers to our preferred resources and gather, gather, gather. Once done, the villagers will go back into the gates and we will go back to being enemies. Both players now get to spend those resources however they please: blacksmith upgrades, troop upgrades, more buildings, troops, etc. Then, once we're ready, we send whatever force we can to fight in the middle plot. Whoever wins will then own that plot. They'll own five of the nine.

A new grace period will begin, where the villagers get 8 minutes to gather resources, then we can spend them as we please. Whoever lost the first battle will be on the offensive trying to take the middle plot. Whoever wins that fight, a new grace period will begin with only six minutes, and the role of attacker switches to the other player. We will go back and forth defending and attacking with a six minute villager freedom moment between brawls until one player destroys the other's capital and thus owns all nine plots of land.

There will be a few basic rules, which aren't super important to this explanation. But I should mention three things:
1.) There is a three castle limit through the entire game. And only one castle can exist outside your capital-plot at a time. So it's very important where and when we decide to build castles.
2.) Trebuchets will be de-activated, as the defending team will not be able to leave their plot to go destroy them.
3.) No docks. Its purely land war.

Now, all of this said, I thank anyone who stuck around to hear about this silly little game of mine. And I am eager to hear what civilizations you think would be the best and why. And, if you played this, what you think you would do?

Resource gathering is big, given that we have the same amount of villagers. Civs with gathering bonuses have a big advantage in that department.

Late-game defensive civs, I'm thinking, may have a huge benefit when it comes to the defending turn. But I wonder if examples like the Byzantines may be unable to deal a big enough blow on their attacking turn. Thoughts?