
Running out of options, I connected the device to a Linux station and ran a logcat command during a test call. There are no ROMs available for this tablet, so updating Android itself is a no-go. A restart to factory settings didn't help.

I believe the evidence points to a Skype bug or compatibility problem. Other apps record audio flawlessly, and the issue persists even when using headphones. The integrated microphone and the microphone jack were ruled out as culprits through testing. Now, all accepted versions exhibit the same buggy behaviour.

I started trying older app versions until I found one that worked, and he stuck with that one until it was finally phased out, months later. All it could be heard on the other end was a constant, static buzz. My uncle bought a cheap MD700 tablet (running Android 4.1.2) and strongly desired to use Skype on it, but for some reason the application didn't recognize microphone input.
