I honestly don't know how you're managing to have all these problems.
Can you please try to isolate your issue to one thing at a time? Now you're having issues creating extensions? How are you installing your machine?
Here's what I'm going to do, right now. I'm going to create a new VM, with this ISO:
http://downloads.freepbxdistro.org/ISO/FreePBX-10.13.66-5-x86_64-Full-1441992502.iso
I'm going to create a PJSIP Extension, that only allows G722, and I'm going to connect to it from a SPA504 phone, as I have plenty of those handy (Edit: Used a softphone, so I could record everything) I'm then going to dial *43, and then hear Alison's lovely voice.
If it doesn't work I'm going to be amazed, but, I'll figure out what the problem is.
Step 1: Installing new distro!
Works For Me(tm):