It is true that two actresses have been cast to play Azula and Toph Beifong, however, there is no confirmed information about who will be playing them.
As of today, October 26, 2023, the names of the actresses cast as Azula and Toph have not been publicly released.
The production team has been very secretive about casting information, likely to build up excitement and avoid spoilers.
Keep your eyes out for official announcements and news from Netflix or the production team for more information on the casting!