After the plot twist with Luffy's fruit, I doubt that Oda will reuse the same idea as well for Blackbeard. Luffy's fruit had its name and true nature changed because of the danger it imposed to the WG historically, hence they tried to cover it. Furthermore, Blackbeard seems to be pretty knowledgeable regarding the history too and was specifically searching for the Yami Yami no Mi for decades, calling it a special case even among Logias. With Katakuri's fruit we know, that there are "special" paramecias too, which possess properties of other types of DFs.