I really like the spirit of this thread, but some of this feels a bit overboard. I’m very much on team “find a way to make natives relevant without making them op,” I just don’t know giving all of them 5 techs is the way to go. Maybe that’s a matter of personal preference, but I’d rather not drastically change all that much. That said, I’m not opposed to targeted changes to units and techs. In particular, Seminole and Maya stand out as lacking a tech each. If I might bend the rules, I’d like to address each:
Seminole
Seminole Bowyer - I agree with OP’s assessment that +15% archer attack for 250w 250c is underwhelming given the price and increasing it to +20% would be a nice buff. Alternatively you could keep the effect the same but reduce the cost to 200w 200c.
Seminole Guerilla Wars - I think this tech should still grant Seminole Sharktooth +3 multipliers vs buildings for their siege attack (x4 in total) but it should also give all archers +1 multiplier vs buildings (x2 in total). This would greatly improve the value and applicability of the tech without a) making it busted (hopefully) and while b) keeping the bulk of the effect on the Seminole Archers so they retain something of a niche. Now, if you really wanted to get crazy, this tech could also increase the range of archer siege attacks, though that’s probably overkill.
Unnamed 3rd tech - I’m not so strong on the lore so please bear with me. Most native tps have a mix of military and economic technologies, so I’d like for the Seminole’s 3rd tech to be economic. I suggest it should increase the gather rate of all sources of food (hunts, livestock, berries, fish, and mills) by 15% for 200w 200c. Think of this tech as the food equivalent of the Navajo coin gathering tech Navajo Craftsmanship. Going off that tech, this seems overpriced, so you could argue for adjustments to the numbers, but those are the finer details. In game, I think this works well since the maps Seminole are found on (Florida, Carolina, etc) tend to be high in natural food, so this tech can be put to good use. And since all civs need food, this gives those like Dutch and India who don’t make their own archers a reason to ally with Seminole (aside from making Sharktooth of course).
Maya
Maya Cotton Armor - gives +20% hp to hand infantry for 250w and 250c. Great tech imo, no major changes necessary. You could tweak the numbers if you wanted, e.g. lowering the cost to 200w 200c to bring it in line with Infantry Breastplate and Zapotec Cult of the Dead, but it’s fine as is. If I were stretching it, you could tack on +.1 melee armor (or I guess +10% after the last patch) but that’s really unnecessary in my mind.
Maya Calendar - improves the gather rate of hunted animals and mills/farms by 10% for 120w 120c. Another great tech, effectively Steel Traps and Seed Drill in one tech for cheaper than either. Again, you could play with the numbers, but I think the concept is solid as is.
Unnamed 3rd tech - For this tech, I’d like to reference one of the civ bonuses from AoE 2. A tech that reduces the cost of foot archers, say by 15%, could work but might be overpowered for civs like British or Japan. Moreover, it’s kinda boring for me. Instead, I think Maya’s 3rd tech should increase the gather yield of all natural resources (hunts, livestock, berries, trees, mines, and fish). My first thought is the effect should be just 5% and cost 100 of each resource. This would put it in line with Klamath Work Ethos. If you think that’s too low, I’m not sure the yield bonus should go higher than 10%. Though, perhaps Klamath Work Ethos should also be improved to 10%, and in turn Sufi Fasting to 15% or so.