This raises one of the biggest sets of unanswered questions all having to do with Fantasyland Theater, the tunnel under the RR tracks right next to it, and the Expansion Pad just West of Toontown (one report has it designated Frozen show building on a blueprint).
My rebel spies report that the concrete RR tunnel on top of the vehicle/pedestrian underpass is now completely exposed. There's no indication whether it will remain or be demolished to accommodate the sharper curve needed to transition the new RR route into Toontown Station. If they reroute pedestrian and vehicle traffic in between the Millenium Falcon and Frozen show buildings, then they could completely demolish the existing underpass. This would permit a new tunnel under the RR tracks to access the alleged Frozen show building from the ride entrance where FLT is now, along with the Arrendale area. One hears that the Magical Map cast's contracts were extended through Feb. 2017 rather than a full year into May 2017 and that the show will NOT go back to seven days this summer. Among some people around the Theater it is believed that FLT will be demolished at some point, but the emphatic official word is that there is no plan to close Magical Map.
I infer from this that they may have committed to the Frozen plan and are putting the infrastructure in place during this massive construction effort. But that's just guesswork on my part. If reports of GotG ToT coming next year and possible Marvel expansion in DCA are correct, then I question whether anything would happen with Frozen until a year or two after SWL opens.
Note: No Bothans were harmed in acquiring this information.