Great to hear you got him working……But the process is not easy.
I did notise that alsamixer were at zerro to - so adding to the script to set it to 75% would be a good idea.
I dont understand why you nedded /home/pi/mycroft-core/dev_setup.sh as I remember that that to is done in the scrpt. I did when I did run it…Strange.
I think the picroft scrit could benefit from a rewrite, so installation of hardware were in differet scripts one for every hardware one will write installation for.
That would make the installation of picroft simpler - get mycroft up and running, and then add hardware. But that is just my opinion.