APE
Inspired
I don't know if this will work when Scarlett is connected. I tried it like that before and there were problems with system preferences and which device handled sounds. Also, sometimes I would get processed signal through axe FX like delay and flanger on skype calls.You have the AxeFX usb connected to your Mac? If so, choose the AxeFX as the input/output device, not the Scarlett. Then Input 5 will be your dry signal. Inputs 1&2 will be the wet signal.
Output will go to your AxeFX. If instead you want the output to go to the Scarlett, create an aggregate device that combines the Scarlett and the AxeFX and choose that aggregate as your I/O device.
I'm trying to hire someone to help me connect the cables and set the right signal flow... Not sure what to do here...