Nokia 8.1 has a double channel LPDDR4X type of 4GB RAM.
No. Nokia 8.1 is not a water-resistant phone.
Yes, Nokia 8.1 comes with headphone in the box.
Yes, Nokia 8.1 does have the fingerprint scanner, which is located at the rear of the phone.
Yes, Nokia 8.1 does have OTG support.