A few questions about android 7 on a new phone
Apparently, on dual SIM phones, this is normal. The provider name will only appear on the lock screen. 

Also, in the quick settings menu, it is normal to see the 'no Sim' setting. It's there in case you do insert a second Sim, you'll be able to change different settings.

There is no problem with changing the phone number in Sim settings, to your current number.