good point @GlennO
if you send analog signal to the Focusrite and the Focusrite doesn't play correct audio, then it's most likely something to do with the USB. you've confirmed already that analog out of the Axe2 sounds fine. the issue keeps happening when you use USB.
when you tested Spotify etc, did you set the Mac audio output to the Axe2? not anything in Logic, but the Mac sound in System Preferences > Sound > Output. does that work with either the Axe2 or Focusrite?
do you have another USB cable? try a different USB port?
normally, installing the driver, plugging in a USB cable and pressing play immediately sends computer through to the Axe2. with a USB cable or computer issue, this may not happen, and it seems that's the issue here.
also, with the Focusrite and Axe2 USB plugged in, can you open Audio MIDI Setup? it's an app on the Mac. when you do, the Audio Devices window should pop up. can you screenshot it with the Axe2 clicked on in the sidebar? it would look something like this (i have nothing plugged in right now):
all that said, it'd be much easier to help if we were right there in the room, or could remote your computer or something haha. text is difficult and makes it seem more difficult than it actually is.
summary: try another USB cable and USB port. it must be something simple.
