If you are using the Lip input jack with two switches, you cannot use the input named "lip", it must not appear in the configuration file. You will need to use the inputs named "digital_input_5" and "digital_input_6".
Also, the Lip sensor cannot be plugged into the Lip jack at power up if you are using switches for digital inputs. The lip sensor is not just a switch and the quadstick detects the difference at power up.
If another IN jack is available, why not just use that? It is simpler and doesn't have these other rules.