Nice build! Apparently, you were more successful in desoldering the volume encoder from the Arylic board than me 
. In my post, you can see how I broke the encoder and almost broke the board. Thought I could make it without a desoldering gun but - nope 
.
I saw that you used the USB-A port of the Arylic board. This means that you can play music from an USB stick, right? In my build, I used the Micro-USB port and cannot play music from a stick but can connect the box to my computer to use it as an external sound card and can also program the internal EQ of the board. Don’t get it why they provide two different USB ports with different functionality instead of one ‘do it all’ port.
Regards, Sven