Moto Z2 Play is quite light weight. It wighs just around 145 grams.
Yes, Moto Z2 Play is a metal body phone.
Moto Z2 Play SAR value are as below:
SAR Value (Head): 1.455 WKg/1g
SAR Value (Body): 1.24 WKg/1g
Yes, with the help of MicroSD card, you can expand the storage up to 2 TB.
Yes, Moto Z2 Play comes with the inbuilt battery.