Willem of Maya wouldnt make any sense, the extra advantage of the Ball Court is that it is paired with EXP, so you have the extra health in every city to support 2 more population points.
Sury of Maya would be the best combination if wanting to get the best advantage from the Ball Court - half cost granary, library, ball court and harbor.
Ball Courts are better than both Hammams and Barays too. In most games you dont need to build 100
aqueducts that early on, and an 80
Ball Court is a much better investment for +3
than any other happy building in the game, perhaps except for hippodromes. With Pacal being Financial, you can also delay both CoL and Monarchy and go for Construction before CoL. You might even be able to grab some nice tech trades with this too. Alternatively on an Archipelago map with GLH, Compass before Writing will let you backfill almost everything through tech trading, along with getting you super cheap harbors for your GLH economy. Fin + Exp are simply beast traits for water maps.
Pacal of Carthage is also a very strong combination to try out for 50
Cothons, but you lose the
bonuses of either Hannibal or the Ball Court to gain this advantage, so you will need Monarchy sooner (Compass > Monarchy > Currency is very strong for this, courthouses dont stand a chance against EXP Cothons + GLH anyway, you will have 5 trade routes per city very very fast).
I forgot its very easy to trade compass for monarchy too. Maths, Alpha, Monarchy, Calendar, Aesth, the AI will give you any of these plus any ancient techs you skipped for Compass on Immortal+.