I have shares in several of the last confirmed blocks with no payouts yet. Is everything ok here?
Yes, just wait the next block.
It's PPLNS with n=10000, you need a minimum of 10000 shares on the pool(in total) to have the expected payout per block.
With your hashrate, it will not take longer than 1 or 2 block (depending on the number of shares of these blocks)