People have many ancestors. While in the first two generations of the patriarchs, some additional wives were secured from the homeland, that is it, and even during this time, some wives were secured from the native population.
The incident of Melchizedek in Genesis points to a memory of having been linguistically distinct—quoting the RSC from Memory here—”the valley of SHavah, that is, the valley of the King”-—the Persian word which gave rise to the more modern term Shah is pointed to here, but that it needs to be translated in text points to the language itself having been lost.
If the Pentateuchal laws had been followed closely after the Exodus the people would have remained culturally distinct, but the second half of Joshua points to “diversity is our strength” being used as an alternate approach, with the result that in Judges the chosen people have effectively become culturally blended with the native population. Having one (or even several) ancestors that aren’t in common doesn’t guarantee anything.
They seem yo have far more than several ancestors in common.
Canaanites and Hebrews genetically are nearly the same people.
And linguistically phoenician and hebrew are sister languages