Yes. Quite a lot of merchants do not ask for CVV/CVCs (Amazon being an example).

Yes, the CVV is not required. If you think about it, it is obvious CCV isn't since many self-serve card swipe machines (gas stations, grocery stores, fast food restaurants) don't ask you for it.

Yup -- you can authorize a card with a missing, or even incorrect, CVV.

I work at Balanced payments, and this frequently trips up a lot of people. If incorrect CVV information is entered, we note that in our response, but it's up to the user of our API to decide if they want to accept that card or not. (We also use this information as one component of many in our internal fraud systems, of course).

Yes. Physical transactions, card present, with chip and pin have lowest txfee.

You can run a card with only a number and exp even. No AVS at all. Just higher cost higher risk.