I doscvered today, on Muppet Wiki, that it appears Season 16 is completed in terms of summaries. Many or all of Season 16 have images from street scenes and the episode number stills.
I've seen some talk on talk pages that suggested they were finished, I wasn't sure if they were really close or if they were complete but still needed some images.
I thought I saw somebody on this forum remember an episode where Big Bird tries to get Uncle Wally to meet Snuffy, only for Wally to fall asleep when he shows up and Snuffy to not want to wake him up, and then Wally assures Big Bird he does believe Snuffy is real. That would have to be a season 16 episode - is such an episode there? I know there's another where Wally makes up a similar friend as a gag, with his joking around crossing over with Snuffy being just missed. Reading the guide, I'm guessing he believed Big Bird, but is hard to tell (and I guess the other couldn't exist).
Just recently I've been skimming through the season 16 descriptions, wanting to see if I could determine when Wally seemed to live on or near Sesame Street, with the characters page saying he was an itinerant visitor at first (is he listed in the season 16 credits?). I figured he'd move closer to Sesame Street that season, but then found that the episode where Telly waits for Wally to arrive by bus is from season 17 (I was thinking that was 16), so I guess he moved later. I'm interested in seeing if there was a proper episode where he moved on or closer to the street, or if he just started hanging around regularly as if he was a resident with no proper acknowledgement of the change (I've also been interested in tracking Buffy's timeline as a regular/resident on the show, which I did start a timeline for a while back).
If all the season 16 guides are completed, I should look and see if there are any other season 16 episodes, besides episode 2042 and the one where Snuffy joins the Grouchkateers, where Oscar and Snuffy interact (I wouldn't be surprised if there are some where Oscar acknowledges Snuffy without it being noted in the guide).
Of course, if such plots aren't noted in guides yet, it's possible that some scripts changed from final air version to the actual aired version. But it looks like there aren't many left that don't have images, so there'd be very few that could have changed.