Thanks for your thoughtful reply. I speculate about HE, HN, or hybrids of HN being in the Americas early on for two reasons. The first is the appearance of the portraiture in stone, both painted and carved, of people with the apparent appearance of HE and HN. Because there is no current dating of the artifacts, I also assume the possibility of hybridization between HN and perhaps Cromagnon. I suppose the Dennisovians should be thrown into that mix although little is known about them. The second speculation about the nature of the hominids and/or hybrids comes from the dating of artifacts from such localities as Valsequillo, Calico, and the less controversial Diring Yuriakh site in central Siberia.
I agree with the idea that it (in my words) defies logic that ancient man went just about everywhere except the Americas. It also makes sense to me that there were multiple to very many migrations of early man to and from these two continents. With the glacial/interglacial cycles and changing ocean depths, it seems that there were ample opportunities for back and forth travels, especially across Beringia. I think the movement of megafauna back and forth across Beringia is well accepted, so perhaps it's not such a stretch to speculate that man followed them. With this generalized supposition one can look at the dating of Valsequillo, Calico, and Diring Yuriakh (270,000+ YBP) and at least take note. As you stated, new sites are being found at a rapid rate, and supporting evidence for the very early presence of folks in the Americas could come to light at any time.
The voyaging aspect of migration by HE and HN seems fairly well accepted. 50,000-60,000 YBP across the Wallace line is also well accepted, though what folks may have done that I do not think is known. Elephants also swam that route. Then there is the idea that people voyaged from Bali to Flores 800,000 YBP. These were all apparently purposeful movements of human groups. I have no idea why the elephants took their swim. The discovery of ancient tools in Crete was fascinating and a big surprise to experts in that area. The tools found there are, I think, attributed to HN and dated to 130,000 YBP. I was fortunate to discuss this discovery with one of the team members of the discovery, Karl Wegman. He is a geomorphologist based at NC State University. As an aside, he has expressed interest in visiting the mountain site in the Virginia Blue Ridge to do a stratigraphic analysis of the site when I am ready and he has time. Luckily he is only four hours by car from there. Voyaging to the Americas across vast stretches of ocean seems less likely than shoreline/iceline hopping and camping on both northern oceans by HE and/or HN. Whoever was at the Diring site in Siberia had figured out how to survive minus 50 degrees f. As to interglacial voyaging, it may have been the same people, though land travel could also have been their mode.
Why only HE or HN? My thinking is that HE or HN were the best candidates for the initial migrations before possible hybridization with Dennisovians or Cromagnon, but perhaps they hybridized out of the Americas and then migrated or even along the way, pure speculation on my part.
I do not think I have categorically stated that HE or HN were more advanced than AMH. I have said that in the assemblage apparent in VA and NC the people look like HE and HN and that in my opinion their art is more sophisticated than, for example, the art from your links dated 25,000-40,000 YBP. This could imply superior technology and advancement or simply advanced emotional and spiritual countenance expressed artistically.
I do have ideas about the "A" word, but I don't go there in a forum setting. Giants? Large skeletons have been found in Virginia and elsewhere. Pigmys have been found in Tennessee. I know no more than I read about and leave those speculations to others. Ancient aliens? Won't go there either. Image at the top is just for fun. Came up with the piece in Peru.