You could use addressable RGB LEDs, like the WS2812B. You just need to supply power and a single IO line to control them so you don't need any external hardware like MOSFETs.
The ESP32 can read the camera, recognize objects/colors, and control the LEDs without any external systems.
Using ESP32s connected via Wifi and MQTT to a host (Pi or something) would be the easiest way I can think of to coordinate that.
You could also go without a host, by having the ESP with the ball randomly choose another and send the command to it, and connect them all together with ESP-NOW which is direct P2P communication.
(no affiliation and never bought from them, just an example of what to look for)
If you never worked before with electronics, however, you'll probably also need some basic equipment to test things and/or add functions (say you want one more LED, or need to add/replace a capacitor, drive
more current with an i/o line etc.).
Take also a look at the beginners section at the EeevBlog forums. It contains some good advice on how to set up a basic workbench: https://www.eevblog.com/forum/beginners/