I don’t see why Warner wouldn’t give Swing Time to Criterion, especially as they’ve given Criterion a decent amount of their high-profile classics over the past few years.
They did indeed put the new restoration up on YouTube, though for a while they did have an older transfer, which has been supplanted by the new transfer.
I quite agree that Waterloo will more than likely be a standalone release (a Criterion War and Peace will probably be expensive enough without adding Waterloo to it). Also, Criterion’s releases from Mosfilm seem to go by what Mosfilm has Janus tour (though we’re still waiting on Come and See)...
A few people on the other forums have suggested that the rabbit hole is actually for Bondarchuk’s War and Peace (the little pebble-like specks are apparently peas). And considering Janus tweeted about doing a tour of that one a few weeks ago, it kinda makes sense that Criterion would be hinting...