Won't help. It gets the information from the telco provider, and does not require GPS or any other fancy hardware.
It helps in the sense that it's difficult/impossible to browse the web on dumbphones, so they won't get your IP in the first place.
Might as well keep the iPhone and turn off mobile data and wifi.
I think a pre-paid (burner) phone would be anonymous.
Not true. If you refill using a credit card then they collect the info at that time. I use T-Mobile prepaid and they have all my info except my name.
Just use a VPN on your phone. Then the IP address accessing websites won't be the same as the IP address from your telco. Surely that would prevent a lookup of your details?
Cannot IP address be leaked via WebRTC or similar technology?