Ubiquitin, the definition you refer to is for “by” as an adverb, not as a preposition. So you can certainly stop by at your cousin’s home, but you cannot, in English, stay by your cousin, or even by her home. The use of “by” in that sense is restricted to Jews and Germans, because it is not the English word “by” at all, but the German word “bei”.
You would have been better off citing the 11th definition of “by” as a preposition, “in the opinion of : from the point of view of. // OK by me”. I believe that this usage derives directly from Yiddish, but is limited to that form. It does not extend to all the other uses German and Yiddish have for “bei”, such as “at”, or “with”.