An iPhone w/o a SIM shows Hello Apple welcome screens upon login every time. After clicking the Home button, it prompts for wireless network, and then Apple account for activation.
Turning off an iCloud did not make a difference.
Turn off the Cellular data option works temporarily. You can lock and unlock for a while, but after the phone sits around 30 minutes, the next unlock prompts again.
( Settings --> Cellular --> Cellular Data toggle to off. )
Turn on Airplane mode, then re-enable Wireless and Bluetooth.
Activate while connected to Mac and iTunes.