@pandasnail: Sounds good with 1 and 2. I think I forgot about Japan's UA there. Can you post or give me your changes so I can incorporate it? (because I'm lazy

)
For the Caravel, all I have is this, then I go into your files and delete the line that deletes the Ocean Impassable promotion from Carracks The I change their movement to 3, again right in your file. For this to really work tho, there might need to be a bigger CS gap, not sure. And there's also the question of which the Trireme and QQ upgrade to in this scenario.
UPDATE Units
SET ObsoleteTech = 'TECH_NAVIGATION', GoodyHutUpgradeUnitClass = 'UNITCLASS_PRIVATEER',
WHERE Type = 'UNIT_CARAVEL';
UPDATE Unit_ClassUpgrades
SET UnitClassType = 'UNITCLASS_PRIVATEER'
WHERE UnitType IN ('UNIT_CARAVEL');
And then this for giving Japanese Carracks their UA
INSERT INTO Trait_BuildsUnitClasses
(TraitType, UnitClassType, BuildType)
VALUES
('TRAIT_FIGHT_WELL_DAMAGED', 'UNITCLASS_EE_CARRACK', 'BUILD_FISHING_BOATS');
to 3: I'm fine with it as long as you guys come up with the changes since I haven't had the time to play a lot at the moment. Moving UUs around shouldn't require any LUA.
So I did some 'historical research' (reading Wikipedia), and it would seem that the Cossack is the only one of the three Cavalry Uniques that can be moved back and sustain historical accuracy. That actually suits my selfish interest well, because I'm not a fan of the Winged Hussar promo Gazebo put on it. So at least for my own games, I'm gonna make it a stronger Ulhan with just the increased damage against wounded promo. New promos is the part I fear might take LUA. Once I've done it, I'll post it, and you, phantom, et al can decide about incorporating.
As for a foot unit, the three choices to move to Line Infantry are the Musketeer, the Caro and the Minuteman. Musketeer are maybe the best choice by my super super in depth research, but that puts France's power even later, probably not going to work. I think I would pick Minutemen, since by that part of the game I don't use the Archer line as much now that I have Cannons. Let me know tho, you or anyone else! Whatever's chosen if anything, again, I'll write the SQL and post here. (Also given the ~somewhat~ historically inaccurate novel, I guess Musketeers could be Two Handers.)
to 4: No clue about the EUI tooltip.
So this bit was in reference to the Samurai. I wasn't sure at the time of my last post, but I've made sure, and yeah, Longswords upgrade to Two Handers and Samurai upgrade to Tercios. Probably an oversight, but I actually think it might be better to have everything upgrade to Tercios. I know it doesn't make actual sense, but Two Handers compete with Cannons for Iron. Two Handers are solid units for sure, but if I only have three or four Iron at that point, I'd much rather have Cannons and Tercios than Two Handers and Muskets. Which might mean not upgrading some of the most leveled up units. And while I can figure it out, I worry about the AI not saving their Iron for Cannons.
Finally, like phantom said, its worth considering moving Two Handers to Chemistry, a rare bottom tech that doesn't have any military units.