I definitely lean to the interpretation of incest. One thing I’ve learned from listening to theologians is that the language of the Bible is extremely deliberate, as well as highly self-referential. The fact that the phrase “the nakedness of his father” is used makes it almost certain that the reader is expected to take note of its appearance elsewhere in the Torah, and use that context to interpret the Genesis passage. Canaan is very likely a child of incest, just like other rivals of the Israelites are depicted as children of incest through Lot and his daughters.