In a new interview with Dream Island's chairman of the board of directors, he says that in the future there's potential to open additional Dream Island indoor parks in St. Petersburg and Yekaterinburg but they would be smaller in scale with the Moscow park being the flagship. These two other cities are the same cities where the DreamWorks indoor parks were going to be built.
Sources: https://stroi.mos.ru/interviews/amiran-mutsoiev-luchshii-sposob-vospitat-dietiei-eto-podarit-im-schast-ie and https://www.google.com/maps/contrib/110518321928980568800/photos/@55.6940611,37.6771015,3a,75y,90t/data=!3m7!1e2!3m5!1sAF1QipNqk6bL-uksPk3u9I1iRUVZKTHEE4hFZQcZK0C9!2e10!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipNqk6bL-uksPk3u9I1iRUVZKTHEE4hFZQcZK0C9%3Dw365-h273-k-no!7i4608!8i3456!4m3!8m2!3m1!1e1