According to an Instagram post by David Miller, the Rivers of Light team is set to finish up dress rehearsals in “the next week or so”.
David Miller is a Manager for Technical Direction and Systems at Walt Disney Parks and Resorts. He oversees technical aspects of live entertainment for the company.
Of course, this is not official information, but definitely lines up with a the rumored timeline of a mid-October soft opening date. Hopefully we will get some official information from Disney soon.