You'll need to get your Bitcoins taxed tho, as far as I know Poloniex is going to require you all kind of credentials, not sure how Bitifinex works tho.
At the moment you can feed nonsense details into Poloniex. If you're crypto only Bitfinex don't require details either. That might change very soon.
Yes I believe thats correct. As long as you dont want to deposit or withdraw in USD or your native currency, you shouldnt need any verification... unless youre based in New York or soon Connecticut