Is there any parental controls that disable in game voice chats, emotes, friend requests, and private messaging from strangers without my kid figuring out how to turn things back on?
I am not sure if it does everything you want, but Blizzard has some pretty thorough Parental Controls. Everything from Social options, to play time and reports, to stopping any in-game purchases.
According to the Support article you need to go to Account Management on the account to set up the Parental Controls
Then you can manage them via the Parental Controls Portal
https://account.blizzard.com/parent-portal/welcome
To remove Parental Controls your child would need access to the separate credentials you used to set up Parental Controls or to contact Blizzard and present ID proving they are over 18 and the registered account holder.
I have never used Parental Controls - so I will be honest I don’t know the full extent of it. But it seems to do what you want it to do, and more - like make sure they can’t play at 2am when you are not awake to supervise!