The only thing I can figure that I change was I'm using a tequnige at the start where I force a bunch of civs to build cities at certain loacations by puting their settler there and surounding them on all sides by my scouts so there's litteraly no tile they can move to.
The Scouts seem unnecessary. If the spot is Settle-able, and sufficiently far from any already settled neighbouring towns, the AI will always settle immediately on turn 1.
This can be seen in e.g. the Mesopotamia Conquest, where all Civs (including Player 1) start with 2-3 Settlers, each placed on a 'historical' location of a major town of that nation. In several cases, these placements also turn out to overlap Food-bonus resources such as Cows (revealed later with Animal Husbandry) or Wheat -- but the AI happily Settles on top of them immediately, wasting that food for the rest of the game. Conversely, having played the scenario a few times, the human would know to move their Settlers off the Food-bonus, thus gaining faster growth immediately (which compensates for the move).
A similar problem exists in the Sengoku Conquest, where many of the preset spawn-locations are also sub-optimal, e.g. on a Food-bonus, or 1 tile away from freshwater, or 1 tile off the coast. Again, a smart human player would then move their Settler before founding their first town, but the AI will not.
I made some tweaks to Sengoku, to give every clan a stronger start (and make at least one island clan also playable, and tone down the OP Yamabushi and Ninja units, and allow the AI to use Armies, pre-C3X).