Just had a look on github nespi 4 pins and they look the same to me..so script Da Flex posted should still work..
Did you try to run all 3 scripts manually from ssh and see if they are at least working mainly SafeShutdown.py
the other 2 scripts should work on any rpi as they are just kodi-send commands..
Don t forget to first install rpi-tools addon and make all your 3 scripts executable..
-Me funciona el LED y el boton de apagado. No estoy seguro de lo que he hecho...Pero no apaga ventilador, la raspberry sigue con corriente.
-I work the LED and the power button. I'm not sure what I've done... But it does not turn off the fan, the raspberry is still running.
try this one and use the same Restart_Button.sh and Shutdown_Button.sh from this post..see what happens..this is same script from nespi github page just edited a little bit to work with libreelec..
If none work tell us what you r doing step by step and we ll try to help..
remove the .txt from file
-No estoy seguro que hacer con ese archivo. He hecho tantas cosas sin saber cual es la buena o mala que no se porque funciona. 
-I'm not sure what to do with that file. I've done so many things without knowing which is good or bad that I don't know why it works.