Some specific notes on C1: These are from a cursory look and get briefer as I go on. The only strategic resources I paid any attention to were the first three, due to time constraints. I also don't have a good sense for just how much variance in starts and/or realistic opportunity is considered acceptable here. Anyway, here goes:
Japan's start is basically not playable. 2nd-ring Rice + Coast Clams, near the end of the long peninsula, and the only food at the far end of that peninsula are two fish, of which at least one must be orphaned since each can be reached only be a city on a specific tile, and those two tiles (one of which is ON the gems) are just two tiles apart. Also they're alone on a relatively small island with no land food except that one rice (just some FPs) and with (deceptively) terrible island access. Maybe change the rice to a corn, add a one-tile island 4N-1E of the gems, and add another land tile or two south and/or west of the capital where they could legally settle another city? (And ideally placed so that failing to settle exactly 3W wouldn't orphan a fish...) And presumably add a 3rd resource if 3 is going to be standard.
Mongolia's capital food (off-river sheep + 2nd-turn coast crab) is almost as bad, but they have a bigger home island, better island access, and no remotely close neighbors apart from poor Japan. Might be okay by the extremely loose balance standards for a map of this type if Japan is fixed as above, I guess? Maybe make the sheep a pig though (and add a third resource if that's something you're doing). Also they have no horses, so add one of those somewhere nearby.
Rome's capital is the best of these three western civs, but/except they have no river. And it gets way better if they move 1E (and they might even LiPing it to the grassland E-NE, getting gold into the BFC, depending on how they scout). They also have probably the best of the three home islands and are generally isolated. The changes above to Japan might help with this some (more chance for Japan to contest the Roman home island a little? If contesting from an off-shore capital is somehow a real thing?) - especially the part about near-total isolation. Their unmoved capital is another one with just two (food) resources, and they have no close horses until they settle the nearest island.
The little inland sea between France and Azteca (that you created by adding a second land bridge) is exactly one tile too small to allow boats to be built on it except for a city on one of the four tiles (up to two cities total) on the Aztec side that are also on the ocean (and could act as a canal). I don't know if this is a problem though.
France has the only inland start, has just two resources, and none of their iron is close. Their position overall seems very strong to me, partly because they have land expansion options in all directions.
The Aztecs have no close iron and their horses, though not really contested, are pretty far away too. Note they not only have three food resources, all three plus a coast fish are in range of the plains hill marble, to which they should definitely move for the 3h plant alone. (It coincidentally also moves them closer to the land bridges to France.) Maybe switch the marble with the nearest iron?
HRE's two food resources are almost as bad as the Mongols' though not as bad as Japan's. Otherwise, they seem okay, I think? By the don't-balance-much standards, I mean.
Germany is off-river, and has three food resources, none of them above 5 foodhammers. Moving 1SE gives up a turn and a plains hill plant, but goes riverside, gets lots more land tiles (mostly riverside) and adds the pigs, losing nothing but coast. I'd probably do it with map knowledge, but they can't see the pigs on T0. Their iron's pretty far away though not really contested. I'd recommend swapping their start tile (including plains hill vs grass hill) with the tile 1SE and then deleting their corn (or replacing it with iron) to eep them at "just" three resources. Overall, their map position looks strong. (Maybe second to France.)
Mali has three resources, but two of them are coast crabs and the last is dry corn. I'd move the corn to the river grassland tile NW-W of the capital. Iron and especially horses are not very close, though not really contested (like Germany's iron).
China has just two food resources, of which one is second-ring seafood and the other is a plains cow. Their iron, typically for this continent, is kind of far, though much closer to them than to any neighbor. I don't want to call this one uncontested since they have to expand in a lot more different land directions than the previous two civs.
The Zulu have three food resources plus other strong capital tiles, but their only remotely accessible copper is far away and on an island.
Japan's start is basically not playable. 2nd-ring Rice + Coast Clams, near the end of the long peninsula, and the only food at the far end of that peninsula are two fish, of which at least one must be orphaned since each can be reached only be a city on a specific tile, and those two tiles (one of which is ON the gems) are just two tiles apart. Also they're alone on a relatively small island with no land food except that one rice (just some FPs) and with (deceptively) terrible island access. Maybe change the rice to a corn, add a one-tile island 4N-1E of the gems, and add another land tile or two south and/or west of the capital where they could legally settle another city? (And ideally placed so that failing to settle exactly 3W wouldn't orphan a fish...) And presumably add a 3rd resource if 3 is going to be standard.
Mongolia's capital food (off-river sheep + 2nd-turn coast crab) is almost as bad, but they have a bigger home island, better island access, and no remotely close neighbors apart from poor Japan. Might be okay by the extremely loose balance standards for a map of this type if Japan is fixed as above, I guess? Maybe make the sheep a pig though (and add a third resource if that's something you're doing). Also they have no horses, so add one of those somewhere nearby.
Rome's capital is the best of these three western civs, but/except they have no river. And it gets way better if they move 1E (and they might even LiPing it to the grassland E-NE, getting gold into the BFC, depending on how they scout). They also have probably the best of the three home islands and are generally isolated. The changes above to Japan might help with this some (more chance for Japan to contest the Roman home island a little? If contesting from an off-shore capital is somehow a real thing?) - especially the part about near-total isolation. Their unmoved capital is another one with just two (food) resources, and they have no close horses until they settle the nearest island.
The little inland sea between France and Azteca (that you created by adding a second land bridge) is exactly one tile too small to allow boats to be built on it except for a city on one of the four tiles (up to two cities total) on the Aztec side that are also on the ocean (and could act as a canal). I don't know if this is a problem though.
France has the only inland start, has just two resources, and none of their iron is close. Their position overall seems very strong to me, partly because they have land expansion options in all directions.
The Aztecs have no close iron and their horses, though not really contested, are pretty far away too. Note they not only have three food resources, all three plus a coast fish are in range of the plains hill marble, to which they should definitely move for the 3h plant alone. (It coincidentally also moves them closer to the land bridges to France.) Maybe switch the marble with the nearest iron?
HRE's two food resources are almost as bad as the Mongols' though not as bad as Japan's. Otherwise, they seem okay, I think? By the don't-balance-much standards, I mean.
Germany is off-river, and has three food resources, none of them above 5 foodhammers. Moving 1SE gives up a turn and a plains hill plant, but goes riverside, gets lots more land tiles (mostly riverside) and adds the pigs, losing nothing but coast. I'd probably do it with map knowledge, but they can't see the pigs on T0. Their iron's pretty far away though not really contested. I'd recommend swapping their start tile (including plains hill vs grass hill) with the tile 1SE and then deleting their corn (or replacing it with iron) to eep them at "just" three resources. Overall, their map position looks strong. (Maybe second to France.)
Mali has three resources, but two of them are coast crabs and the last is dry corn. I'd move the corn to the river grassland tile NW-W of the capital. Iron and especially horses are not very close, though not really contested (like Germany's iron).
China has just two food resources, of which one is second-ring seafood and the other is a plains cow. Their iron, typically for this continent, is kind of far, though much closer to them than to any neighbor. I don't want to call this one uncontested since they have to expand in a lot more different land directions than the previous two civs.
The Zulu have three food resources plus other strong capital tiles, but their only remotely accessible copper is far away and on an island.