Olaf's Snow Fest is slated to end on April 30 and Frozen Fun is slated to end on May 15. I think the only thing that has been confirmed is that the A&E meet and greet will continue beyond those dates. The additions to Storbyook Canal boats will remain and I would guess that Frozen at Fantasy Faire will also continue (although perhaps they'll put Tangled and/or Beauty and the Beast back into the rotation). My guess is that the end of Frozen Fun means that Freeze the Night and the Sing-A-Long will end on the 15th.
I posted the Blog Link in the original
Mad T Party is Closing thread earlier, so it looks like the folks that said the Mad T Party performs that told them they'd be returning in May were right!