Let's suppose that they have it backwards.
What if the original people with the red-hair, blue eyed genes originated in Sundaland and after their home-land submerged (Sundaland was about the size of present day India), made their way up the river valleys of Asia, across the steppes/mountains and into Europe 8,000 years or so ago. If the dispersal point was SE Asia, some would have gone searching for a new home land by sea and some by land...and, they would have gone in all directions perhaps explaining the persistant stories of red-headed people everywhere.
Note: I'm not discounting your ideas. They hold as much water as mine until proved -- that's how we learn. I repeat -- conversing with you is one of the best things on this forum, I learn so much!