If all the connections internet (data and wifi) and location services are off how can I find or erase a device that has been stolen before someone access my device?
if someone stills a device of course the first action will be switch off all the connections or shut of the device.
iPad mini 3, iOS 12
If you had a passcode on your phone no one can access its contents.
If the phone has no Internet connection you can’t do anything with it, but you can go to https://icloud.com/find and put it in Lost mode. That will lock it the first time it connects to the Internet.
See also this Apple support link——>If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support
If you had a passcode on your phone no one can access its contents.
If the phone has no Internet connection you can’t do anything with it, but you can go to https://icloud.com/find and put it in Lost mode. That will lock it the first time it connects to the Internet.
See also this Apple support link——>If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support
Follow this
If your iPhone, iPad, or iPod touch is lost or stolen
find and erase devices
