Yes, Samsung Galaxy J7 comes with non-removable battery.
Well, Samsung has recently announced that they will try to provide as many updates possible. But they have not said anything specific with respect to Android 8.0 but we hope that this model should get the update in future.
No. Samsung Galaxy J7 Max does not have the Gorilla Glass protection.
Yes, we do have assured money back guarantee, if you return the product.
Yes, you can put 2 4G SIMs and a Memory card also at the same time in Samsung Galaxy J7 Max. Galaxy J7 Max does have 2 dedicated sim card slots and a dedicated slot for memory card.
Samsung Galaxy J7 Max is worth considering if updated software and a great camera are your priorities.