I'm so glad that you have protected yourself from this enormous counter-party risk before anything ominous really happens.
I'm not sure why it is that some people seem to have no problems withdrawing whilst an army of others have been having problems for months. Me being one of them.
I read The Willy Report some time a go which goes through all the events leading up to and after the demise of gox. It's eerie how similar poloniex's recent actions have played out.
When something is usually too good to be true, it usually is, and Poloniex have certainly created quite the lucrative market on their exchange perfectly conducive to luring in a very large and significant part of the crypto community. Whether or not it turns out as bad as mt gox, if bad at all, remains to be seen. But I certainly have my skin in the game. Nervous times for me!
Tonight I just got my SBD deposit into Poloniex, traded to Bitcoin, and then completed a withdrawal to Coinbase in about an hour which was surprising because I did not think it would work! For your deposits in limbo, did you ever get the emails asking to confirm withdrawal? I think my withdrawals say awaiting approval until I click the link in the email confirming I want to complete the withdrawal. Is there a way to resend the email or did you already go through all that and nothing worked?