I got a new phone and factory reset the old one hoping my child could just use WiFi to play games. Now I can't get the phone to activate????? Can I do this?
Not sure what you mean by "activate".
Activate where? If you don't put a sim in it, it will work on WiFi. To go online, it will need to be associated with a Google account/Gmail address..
If you use your Gmail, your child will have access to everything you do online. If you create a new one, you may not have access to what the child does online unless you know their password etc...