I absolutely think there was an earlier southern migration from New Zealand and Australia. From the PLOS one paper...
"Human genetic and skeletal studies provide different types and scales of information and varying opinions on the origin and diffusion of early South Americans [17–19]. Archaeologists generally disagree about the origin of South American material culture. Two different perspectives have been proposed to explain the earliest known stone tool technologies, each with varying implications for the interpretation of early sites. The first is that Clovis bifacial technologies reached South America ~13,000 cal BP in the form of Fishtail projectile points [3,6]. This model is based on diffusion and comparative morphological analyses of fluted point styles and leaves little room for independent technological development in South America. The second is that North and South American tool assemblages, including both bifacial and unifacial industries, are different adaptations to different environmental and cultural conditions, yet both derived from an earlier currently undefined technology somewhere in East Asia [1,4,5]. The arguments advanced in support of the second model at present hinge on evidence recovered from sites such as Monte Verde II in south-central Chile [13,14], Gault and Friedkin sites in Texas [9,10], Cactus Hill in Virginia [11], Paisley Cave in Oregon [8], and possibly other sites [12,15,16,18,20–22], all of which contain varying types of bifacial and unifacial assemblages dating ~14,000 cal BP or earlier. There is no doubt that some lingering influences and contacts existed between North and South America, but some of these appear to have taken place after the initial colonization of the southern hemisphere and, in some later cases, may even represent reverse migrations from south to north [7]."
If you go past 12,900 years ago...oceans were around 300 feet less than what they are now. When the glacier over North America melted (in a hurry), it had dramatic affects on coastal regions...raising up the water levels.
A couple of years ago, I was reading through a piece on maps, and there’s this map which has been around for generations...showing coast regions of Antarctica. It’s a port to port map...meaning you used it for sailing from one port to another. It begs questions because it shows the bays and harbors along Antarctica region. But you’d have to go back a heck of a long time ago, when this region not have been covered with ice or glaciers.