No. LG V30 Plus does not have the in-built FM radio but there are plenty of Android apps available and you can download the same from Google Play Store.
Yes, LG V30 Plus can record 4K videos very easily as the rear camera has the highest video recording resolution of 3840 x 2160 pixels. You can also record 4K videos with Hi-Fi audio recording.
Yes, LG V30+ is a dual sim mobile phone.
No. LG V30 Plus does not come with B&O headsets in India.