I agree with the interpretation of KANT you are giving. The Philosopher
Immanuel Kant always claimed to have Scottish ancestors, but his great-grandfather
Richard Kant immigrated from the Baltic area, most likely from a place called Kantweinen near Prökuls. This again may contain the "kant" element (edge) you mention.
Source:
Rosa und
Volker Kohlheim: Familiennamen, Herkunft und Bedeutung, Duden-Verlag Mannheim 2000