3. There was enough liquidity at the peak of bullrun so it was possible to convert ONION to BTC and then to USD or maybe some part even directly to USD.
That was not possible. The maximum volume was 3.20 million on January 09, 2018. I don't think there was enough liquidity at that moment to dump 150000 ONION (@$20). It would destroy the market without any doubt.
However, listing on some bigger exchanges was definitely possible back then but now we are left none.