Control change message 7/10 sets Volume fader/Pan knob for channel strips checkbox: When selected, MIDI Control Change message #7 controls channel strip volume and MIDI CC#10 controls channel strip pan position. Enabling this setting might interfere with MIDI plug-ins and Smart Control mappings.
Instrument Without MIDI Thru Function pop-up menu: The instrument selected here does not pass events through the computer when the instrument is assigned to the selected track. Normally, you would set the No Output instrument here (chosen by default).
If your master keyboard doesn’t have a Local Off setting, you can use this feature to avoid unwanted note doubling when recording:
With multi-timbral sound sources, assign the instrument (usually channel 1) that plays the part that is heard when playing with the computer turned off.
With mono-timbral sound sources, assign the instrument that represents the sound-generating part of your master keyboard.
In either case, you should turn down the volume control of your master keyboard whenever you’re recording tracks for any other instrument.
It’s possible to turn off MIDI Thru for any MIDI track in the Main window by simply turning off the Record Enable button PDF
Logic Pro Instruments: PDF