Due to licencing requirements, we do not provide a software aac decoder. Decoding support for aac is provided on ios and android using those platform’s apis.
For running under emulator, android studio appears to install as a snap by default. Running Ubuntu 20.10 kernel 5.8, I was unable to get audio to play out of any application via the android emulator. Can you confirm that you can play audio from other applications in your setup? It may be worth trying installing android studio via a method other than a snap package if that is what you are using.
For the missing /proc/asound, assuming you are running natively on linux, If you use the output type FMOD_OUTPUTTYPE_NOSOUND, you should be able to run FMOD without alsa. If you want audio output, I’m not sure how you are intending to output audio without device enumeration information. I might need some more information as to what you are doing to help further.