No. Nokia 7 Plus does not have the Dolby audio.
Yes, Nokia 7 Plus in-the-box accessories include a pair of an earphone as well.
Yes, Nokia 7 Plus does have the Bothie feature.
Yes, Nokia 7 Plus does have the OTG support.
Great battery life, immersive display, solid design, and software at its purest, that's the Nokia 7 Plus for you.