Great video and thanks for sharing it
I hear string buzz basically the fret is muting the string ( I call if fretting out ) , part of the setup I do ( on my guitars ) is playing every note on the guitar to see if there are issues I am willing to bet a small truss rod adjustment would fix that IMHO
The reason it is more evident way up the neck is two fold
1) less string mass to vibrate
2) String breaking angle , if you draw a line between the fretted note and the bridge you will see how easy it is for the next fret to mute the string a bit that is where the relief and bridge height balance comes into play.
If you set the guitar flat and fret that note or notes and look to see the clearance to the next fret then pick the note if you look really close you will see it I hope your guitar sound 100% fixable to me !!!!!
One or twice on some other makers guitars I did have to redress a couple of frets that weren't level with the rest, Some folks also swear by having the Guitar Plek set up and of course PTC could also take care of you.
http://www.plek.com/en_US/home/