There's not even any rumors with teeth about Early Frozen Morning.
Maybe this will end up being comparable to what happened with Anna and Elsa. When they first appeared in Norway, their meet and greet started at 11 because the only thing open in Norway before that was Akershus and a store. Because Akershus is open starting at 8, the pavilion isn't roped off or blocked to allow the guests access to the restaurant. So guests who weren't going to Akershus would go up to Norway at 9, just to get into the Anna/Elsa line. And queueing was allowed between 9 and 11. That meant that pretty much nobody had a wait of less than 2 hours in that line. Because if you waited until 11 when they actually started meeting, the first person in line was waiting 2 hours because they'd gotten in line at 9, and the end of the line was already nearly in China and had about a 3-5 hour wait. Of course, the new ride and meet/greet area will be able to handle a higher capacity than the old one could. But it was noted that guests weren't waiting for 11, they were starting to get in line at 9. If the Frozen stuff doesn't open until 11, and queueing is permitted in the pavilion before 11, this will likely happen again.
This got so crazy that they started opening the meet and greet at 9. Which caused people to run like heck from the front gates and IG. The only way to avoid the mad dash was an early breakfast at Akershus. Even then, there were guests who would book Akershus and not even bother to go to the restaurant, they'd pay the no-show fee and just go straight into the Anna/Elsa line. It'll probably be the same thing if the Frozen stuff opens at 9.
Either way you'll have to decide if you want to bother with Future World.