You can bypass all the stuff like finger prints, entering card details, voice recognition. He could set the phone up very quickly with minimal security features too, a 4 digit pin code to unlock or even take off the phone lock completely.
I've tried all this with an old Iphone 6 I've got spare just now and a new SIM compared to the old SIM. It worked and I made a call all within 3 minutes of putting the SIM card into the phone.
A new email account can be in any name whatsoever, he could call himself Shirley Temple if he wanted to on the new account. That only took me 90 seconds to set up.
I still can't work out if his phone IMEI would become traceable with a new SIM fitted to it via the phone networks or Apple. If it can be traced then I would be ruling this out immediately because the police would have then traced the new SIM phone number.
I watch the series Hunted in the UK and the stuff those hunters have access too is unbelievable regarding mobile phones. Not sure if you have watched any of the series, but the technology they have access too regarding phones being in areas is quite amazing.
With Anthony's phone switched off, it would still ping onto the local masts for a while afterwards. Hopefully an expert in the Police has checked this thoroughly rather than just check his itemised bill and online account for calls or texts.
He also may have disposed of his Iphone securely and used a completely different ' burner ' phone to get away.