That's the beauty of as is. Buyer beware. You are not required to disclose anything that is wrong with your vehicle to a buyer. Only if the buyer asks you directly "Does the A/C work?" does honesty come into play. Don't tell if not asked.
Check the ac system, it may be just a simple repair or charge. Doesn't always mean compressor failure
No. Inverter pump works or it does not. Check to see if you fluid movement in the inverter reservoir. 1) Remover inverter reservoir cap. 2) Note the lack of fluid movement. 3) Make car IG-ON or READY. 4) Look at inverter reservoir. Do you see fluid movement? If it is quiet where you are at the time of checking, you may hear an aquarium pump like sound also; the inverter coolant pump. 5) Reattach inverter cap. 6) Fluid movement-inverter pump is working. NO fluid movement-inverter pump need to be replaced, but you woukd have had a some warning lights.
Everyone has different moral standards. What if a person ask "What is wrong with the car?" or "What does not work on the car?" Would such a question be considerd too general, to provide an honest, specific response? A vehicle inspection may not catch everything that is wrong as well.
The seller can (and more often than not does) answer: nothing that I'm aware of. The buyer can choose to trust the seller (which would be naive) or could take that as a strong hint that the seller might be hiding something and move on to the next vehicle.