There is an application called Tasker. Which can be bit difficult to work with for you, if you're not familiar with it. but it's worth learning for your use case. You can make profiles which will get triggered when particular conditions are met. For example, you can start the wifi or turn your phone into silent mode when it's within 100mts of your home, or you can change the default launcher according to your needs in the question. Here you can find basic tutorial for Tasker, which can help you learn more about it.
For your particular use case I found some profiles which can help you,
1) Restore Default Launcher
2) Restore Default Keyboard
3) These are other profiles, you can look into.
Since you can not root your tablet, these are the use cases for the profiles you can use/create without root. (These are just for your knowledge, because Tasker can do lots of stuffs even without root. Which can come handy in some other scenario you want to use in future)
Some ADB Commands I found which can help you,
1) Change the default Keyboard using ADB
2) Enable Location services On or off
To connect using ADB remotely, This answer can help you
The answers in the question above is not using adb shell su, so I'm assuming it will work on non rooted phones aswell (You already found answer for other use cases you mentioned in your question, So hopefully this solves your question).