Gossip Girl Spoilers: Two family members return!

Kristin dos Santos tell us spoilers that could cause not one, but two, surprises to the original GG cast!

Monica in New Orleans: Anything good coming up on Gossip Girl?
Chuck is going to visit Bart's grave on the anniversary of his death, and when he gets there, he won't be the only one paying his respects. Any guesses on who'll pop up? I'm hearing that not one but two family members could be making surprising returns.