I suggest you go to the patent site as there was something published on 7 March by Universal....for a theatre ride system.
So pretty much a patent for a Carousel of Progress style theater.
I would assume Universal does the same thing that WDI does, in terms of having ride systems potentially on the table for the future, but I highly doubt that it means that Sing is a confirmed IP for the park's (as of now).
The more logical move is adding them to the parade, to replace Spongebob once Kidzone closes; as Nickelodeon is probably going to be faded out of the domestic parks in the near future. It's been happening for Hollywood for years, and I'd say that you should expect the exact same thing for Orlando in the next year; especially if they intend to get SNW ready by 2020.
A Sing parade might be the most logical idea or that movie I've heard.
Honestly, it makes sense to test the IP on a small scale, while also getting rid of something that won't make sense with the route that USF is going at right now. It's also the chance for Universal to bring more IP's from their own company into the picture, to remove the third party IP of Nickelodeon out of the equation.
I can easily see them going the way of removing Dora/Diego with a DWA IP like Shrek, and then having Sing to take over the Spongebob floats; allowing all of the floats to stay within the company.
That being said, SLoP.
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I think, with all intensive purposes that it could just be a victim of mere timing. With the DWA accquisition in the Summer, NBCUniversal/Universal Hollywood could of easily decided, that the better action to take; was to add something that has been very well tested throughout the years, critically and money wise.
What it could be, is something in that library but I do think SLoP at this point; is probably canned for Hollywood.
Does that mean it can't come eventually, but in a different form? Perhaps, but it'd have to be in a different location.