Everything seems to work properly now except for one thing: when connecting to the blheli configurator to adjust motor directions, only esc 2, 3 and 4 are appearing when the set up is read. How do I make the first esc be read?
its either not selected or you have a bad connection.
Check power and signal connections.
If you have a volt meter make sure you ESC has power at the ESC its self.
Yeah as @DoomedFPV suggested, as either its a bad connection to the ESC or that particular ESC is bricked :-(… but happy to hear you got your FC working at least!
If your ESC is actually working fine (except for the motor direction and you cant connect to blheli for whatever reason… you can also just swap any two of the ESC to motor wires and that will also reverse the motor spin direction. But best to figure out why its not connecting to BLheli configurator.