Yes, Absolutely. All products sold on OnlyMobiles.Com always carry genuine brand warranty.
As per Samsung brand, Samsung Galaxy J7 Max is not a waterproof device and hence we cannot term the phone that it is a waterproof phone - just because of some random videos. We advise you to check Samsung Mobile India website for more authentic information. Do not believe any blogger if the company is not confirming about waterproof-ness.
Yes, Samsung Galaxy J7 Max does have fingerprint sensor.
Yes, You can. However, the phone shipped with the latest Android 7.0 Nougat OS.
Yes, It has 3.5 mm music jack.
Samsung Galaxy J7 Max is worth considering if updated software and a great camera are your priorities.