You can send commands to your led panel also from EmulationStation's event system, which was expanded recently to support more entry points - https://retropie.org.uk/docs/EmulationStation/#scripting.
There have been a few integration using this method:

https://retropie.org.uk/forum/topic/30528/ https://retropie.org.uk/forum/topic/22195/

As long as you have the commands to control your panel, you can create scripts to send those commands based on EmulationStation's state and operations.