Robert and Lucille had Patchwork Kids.
I mean, if Sidney and Sandy did...
Sebastian didn't really lose an eye in Heidi's rampage.
He wears the eyepatch to milk sympathy out of his readers.Bletch was planning on firing everybody once he had the network deal
Robert and Arthur are the two Feebles in witness protection.
Since The Muppets Mayhem had Peter Jackson say that only two of the Feebles are in protection, something must've happened to the others to land them there: Arthur passed away peacefully in his farm, Sidney was arrested for drug abuse (which he took to cope with leftover PTSD and depression from his acting days), Sebastian was found guilty of plagiarism in one of his books or some other minor crime and is serving a few months to compensate, Seymour became a delinquent in his teenge/adult years and was arrested for robbery, finally Heidi was said to have been released under a new name ten years after her arrest, so no one outside the justice system truly knows she's out there and thus to the larger world she is still in prison.