When to be able to trade in Poloniex?
Only they know. But I don't understand why aren't they listing Stratis. It is top trading coin on Bittrex. It could have 10 of thousands bitcoins trading volume on Polo. Messaging them every day. No answer.
Maybe they want startis have full nodes and then list it. They will test this coin is legit or not. Release means legit, price will be going up and listing on polo