I think people migrated here from Asia, Europe and Polynesia via many different routes, north, south, east and west.
As for the arrowheads, form follows function, and always has.........................
I too believe America was settled from a number of different directions. The Portuguese were fishing the Grand Banks of Newfoundland before Columbus “discoverev” America, so it is certainly possible Basques could have come here. Do we know haw many millenia old that fishing tradition was? Did the Cartheginians use it or the Philestines? Forty years ago I was at Epcot Center in Florida and saw a cup that had figures on it that looked Japanese although it was ascribed to a precolumbian Mexican civilization. It looked exactly like art work I had seen in History and Appreciation of Art while in college. I also have seen Amazon tribal pictures in National Geographic in which the tribal members looked Caucasian, not Amerindian. And these were very isolated tribes, not ones that were likely to be interacting sexually with European Brazilians.
Regarding arrow heads and spear points. Most of the large animals of North America died out around the time the Clovis tradion disappeared around 13,000 ya. There has been plenty of FR speculation regarding this phenomenon. I was at a small museum in a mid south state that had an extensive exibit of locally found stone points. None of them, even the spear points were more than 5 or 6 inches, and the arrows much smaller. This display was listed as around 8,000 years old. Obviously for much smaller animals, although forest bison still existed in that area for which the spear points would have been suitable