Spanish conquerers had a nasty habit of describing basic parts of indiegenous life as muslim in some way. For example, the great temples of mesoamerica including the hueyi teocalli of tenochtitlan are oft called mosques in early spanish sources. Native americans were also referred to as moors regularly by conquistadors. And lest we forget the entire etymology for California, that being a term for a female caliph. The castillians uncreativity in coining new words for the practices of their enemies should probably not be taken as proof that the people the spanish conquered were muslim. As for handkerchiefs and clothing, I am quite sure natives knew how to create fabrics to make basic garments out of, unless you're referring to some specific west african handkerchief, in which I would love to see where that might be mentioned in any colonial reports.

I, along with many academics, doubt that Abubakari succesfully crossed the atlantic. The first force he sent were reduced to one ship by some oceanic disaster, so I dont see why the same fate could not have afflicted Abubakari himself, especially since there isnt any evidence to suggest he made it to the new world. Theres also the possibility that the entire story is a fabrication. The first person to write it down, Al-Umari, was hearing it a couple decades after it had transpired, from a man who had hosted Mansa Musa in Egypt. Theres also the option that Mansa Musa could have made up the story. It is awfully convenient when your predecessor disappears and happens to name you king.