They just show up as a stereo in or 2 mono with WASAPI, there's no multichannel.
The ASIO4All gives you all inputs of all devices (this is handy if you are using 2 devices for recording that are synced with optical or rca cable) but you get that GS Wavetable error thing unless everything else is closed.

I use the WASAPI with the onboard audio for playback/mixing that works good, rather than having a good ASIO interface plugged in and on all the time just for playback. I lent a 16ch USB Phonic Mixer to someone, they used it as a soundcard so it was left on all the time so the internal power supply blew, but I fixed it after replacing a lot of parts, so now I only use the multichannel interfaces for recording only.

https://www.dropbox.com/s/dblos28m48uwfio/AU-Audio-Drivers.gif?dl=0
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