Well, it is another time for the Logician to enter the scene and analyse the sneak peak that will tell us which civilization and which leader will be revealed tomorrow.
First of all, what do we see? Two and half tree. They are right in the center, which is obvisouly a decoy, so let us not focus anymore attention on it. Or, should I say, let us not focus anymore on the fact that they are trees. Because they obsviously are not. Which kind of tree look like this? Some kind of palmier? Nonsense. What you see is cotton plants: a round flower-like thingy on top of a stem. So, cotton it is. The fact that we have proven that it's cotton is important for two things.
First thing: the main use in history of cotton was to justify the triangular trade. Europeans are well-known to be mean-spirited, evil people that do not have any compassion against anyone since the Black Plague. Once they discovered militarily inferior - and thus inferior on every point - people on the other side of the Mediterranea Sea, they then had just one wish: to torture them by making them navigate across the Atlantic. A lot of African people never saw the ocean and thought it was the Hell - or any horrible afterlife African people have, I'm too Eurocentric to bother about that. Problem was that, once African people crossed the Atlantic once, they were kind of acustomed, so it was no use to do it again, the torture was not as effective. So they were dropped in the Americas, where colonists used them in cotton plantation. When humanists lefties went with "human rights" and things, triangular traders said that the Triangular Trade was not initially to torture African but to have a cheap, soulless workers to work in cotton plantation (we now know that it's false, but it was a big controversy in the XXth century). So, by showing us cotton plants, Firaxis is giving us a hint about a civilization linked to the Triangular Trade (evidence A).
But we know that Firaxis always give us subtle hints. We have to look further. The new civ is linked to the Triangular Trade, but not literally: figuratively. We then do have a new civ that will be linked to slavery across sea. Alas, the next two civs, Phoenicia and Ottomans, could fit this loose definition. But under what other name could be defined slavery across sea? Let's try this : Transportation Across Maritime Areas of Human Resources. Or TAMAHR. If we take out the H (because it makes no sound), we have TAMAR, which is the name of the Meme Queen, a clear and obvious indication that the new leader will be a female (evidence B) and that the civ will be linked near Caucasus (evidence C).
Now, we haven't talk yet about the walls-like thingy in the first ground, and frankly I shouldn't talk about it because I'm already completely drunk, but let's try anyway. In which color is this wall? Well, if you change the saturation of your screen, enhance the luminosity, close one eye and squint the other, you will see that they are pink(ish). Pink is a color really close to purple, especially Tyrian purple, so you know exactly where I'm heading: pink being a false color (is you see a wavelenght spectrum, pink is nowhere on it), it is an evident indication that the leader will be false too, aka legendary (evidence D).
Oh, and, yeah, Tyrian purple (evidence E).
Did you remember, in the first paragraph, when I said that the fact that we proved that it was cotton (wow, that's a lot of the word "that") is important for two things? We only showed one. The other one is of extreme simplicity. Did you remember the H we took out the TAMAHR by convenience to prove our point? Well, take it, and replace the second T of COTTON with this H, and behold! The word we discover: COTHON (evidence F).
So, we have an extra T of the word COTTON transformed in COTHON. I could forget it and act as if it never existed. But what also never existed during Antiquity? Tea, a beverage that sound exactly like a T. Which is the indeniable proof that the new civ is an Antique civilization (evidence G).
Looking now at evidence A, B, C, D, E, F and G, we now know that the new civilization is linked to some sort of maritime trade/slavery, located near Caucasus during Antiquity, with a female, legendary leader, linked in some way to Tyrian purple and a thing name Cothon. The new civ revealed tomorrow is then Phoenicia, led by Dido.
And another victory for logic.