Alright, thanks in advance.
So, I'm running
OSMC (kodi, Linux version 4.4.8-3-osmc (root@rpi2) (gcc version 4.9.2 (Raspbian 4.9.2-10) )) on my Raspi B+. I have a
SpeedLink Vigo USB sound card plugged in. You find the output of arecord/aplay and my configs in the OP on github. For now I want to record via the USB device and playback internally (i. e. my TV via HDMI).