“Almost nothing by itself is objectively a kula or chumra.”
OK, I disagree, but I glad you finally stated this outright. We just define it differently.
“Chalav Hacompanies from it’s origins was considered to be chalav yisroel.”
People like to say this, but I’ve never heard a real rav claim that this is actually what he meant, and in fact I’ve had several specify that this is definitely not what he meant.
“Once the Bach/Rema/Others? were not rejected, it has become precedent.”
Lack of rejection doesn’t mean it’s not a kulah. Any real kulah is, by definition, accepted. Otherwise it would just be considered an isser (eg. the Conservative “kulah” to drive to shul on Shabbos).
“And I would be uncomfortable calling that a kula until it could be demonstrated that the earlier sources were of the opinion to be machmir in such a scenario.”
I’ll try to provide sources when I get the chance, but it’s relatively widely known. The gemara explicitly discusses chodosh in chutz l’aretz. The Rema’s lashon is clearly that of someone reluctantly trying to be matir something. The reason there is somewhat of a yoshon revivalist movement today is due to how shaky the heterim have always been, and people are just now learning that.