Solution found! Thanks @Helder.
Issue: Extremely choppy and quiet audio through speaker.
Solution: Added resistors as suggested by Helder which, instantly increased the volume and reduced the choppiness to a very playable level. No other steps were required apart from hookup as shown on Helder's wiring diagram and the config file, both of which are found on page 1 of this thread.
My setup: AIO 2.2A with 5 pin audio jack, Raspberry Pi v1.3, Adafruit Powerboost 1000C TPS61000, and 8 Ohm 1/2 Watt speakers
https://www.amazon.com/gp/product/B00WW ... UTF8&psc=1
Parts Required: Two 75ohm 1/2 watt resistors, Three 1.5 inch long pieces of extra PWM or audio wire and a small piece of perf board.
Resistors from
https://www.amazon.com/gp/product/B0002 ... UTF8&psc=1
To do:
Place resistors into the perf board parallel and adjacent to each other and solder the ends together on one side to make a U shape.
Solder a wire from the bottom of the U, on the side you just joined, to the Speaker - pad on the AIO.
On the other side of the perf board, solder a wire from the end of one resistor to the right side of R15.
Solder another wire from the end of the other resistor to the right side of R16.
Done
You do have extra perf board that you used for practice, right?!

For excellent soldering tips to protect your investment -
http://www.sudomod.com/forum/viewtopic.php?p=21465