Dual remote external mics with iPhone 6?

Hello, I'd like to use my iPhone 6 to video a classical guitarist's performance and be able to capture the guitar's audio in stereo. Is this at all possible? I know there are stereo mics like the Tascam iM2 that plug into the top of the phone via the lightning port, but then the mics are on the phone itself and don't allow any precise positioning close to the performer. Frequently, when the phone is at optimal distance for video, then the mics are too far from the performer for good quality sound.. So remote external mics that can be positioned and adjusted would be preferable. Is this at all possible? I've spent hours looking on line and find nothing about this.

Can the native camera app on my phone even record stereo audio at all when videotaping?

Thanks in advance!

CJ