The upgrades are fine, but I would suggest 3 new upgrades and 1 new unit.
New technologies:
Lever: ‘Maya Holcan Spearman’ gains a ranged attack and bonus damage to cavalry by 1.0. (It also improves his attack on mele)
Mayan trade: (Passive improvement). You have a drip of coins while the alliance is standing.
The Mayans had trade routes through much of Central America.
Limestone mines: : The bastion upgrade is free and moves to the age of trade, and the walls are built faster.
The Mayans will tell you where the local stone mines are.
New unit:
Commoner (Mayan Archer): Warrior with ranged attack who can hunt and is effective against heavy infantry. The Mayans used these weapons for hunting and for battle.
