No. Sony WS623 comes with non-removable battery.
No. Sony NS-WS623 does not have FM radio.
Yes, Sony NS-WS623 does have NFC connectivity option.
Hold down the button 1 for 3 seconds.
You will hear the startup sound.
When the Walkman turns on, the lamp (2) lights up.
Yes, Sony NS-WS623 is meant for the rough usage and it is both - waterproof and dustproof.