I assume by headset you mean something with both headphones and a microphone. I that case, it is both an input AND output device.
yes
Head sets have speakers on two ears and a microphone. The speakers are output devices and the microphone is an input device. So if a headset is an input/output device.
A headset
It depends - if it's just headphones, it's an output device. If the headset includes a microphone - it's both an input and output device.
output devices are
Yes, it should work. But a device with 7.1 output should have an option to output 5.1 and automatically convert the signal.
Output devices.
Speaker, headset, earbud.
output devices are monitor,speaker,printer where you get your output
braille and headset
Lots of companies create output devices.
No you cannot.
Yes! USB audio devices are not just speakers and microphones, they contain also a sound card. So you have multiple sound devices and you can select witch one you use for input and witch one output.