Just a small suggestion- I think it would be rather simple to add armhf and arm32 support for the FreePBX 17 Install Script- and it would also probably make Sangoma more money, because many people would be able to easily run FreePBX on the Raspberry Pi.
Much as I love Pi’s if used in their comfort zone, they just aren’t a good choice to ‘serve’ anything, particularly realtime media transport, there are any number of equally cheap mini pc’s that aren’t attached to the desire to educate school kids ( which I agree with 100%)