Yes, you can use 2 4G SIM cards at the same time in Nokia 8.1.
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 OIS support.
Yes, Nokia 8.1 does have the 3.5 mm headphone jack. It also has Bluetooth A2DP support.