I think the eWeLink cast ♨ eWeLink Cast Update Planning-V1.4 Released on December 1 | Free discussion - #48 by toni.perez.sanchez would be help, try to setup a CAST dashboard for your kids with the devices and charts that you want to share with them, without device settings and other irrelevant settings.
For customizing play sound, it’s a totally new feature called TTS, will take some time to evaluate it, lots of work need to do far as I know.