The Beringia hypothesis has the advantage of not invoking a paleolithic ship construction industry. I know this is all very romantic, but for the moment, there is little evidence beyond some chicken bones that even Polynesians, within the 1,300 to 1,500 years (the settlement date of Easter Island) made it in any significant numbers. The simplest explanation is that multiple groups, some with different genetic heritages, went across the land bridge, some basically settling there until the end of the glacial maximum, and others possibly coming later. Multiple waves don't require multiple routes.