Seems like the only time those are widely stocked here would be for a Jewish holiday, Passover? Not sure. Large Jewish population in Greensboro.
For the Mexican Cokes with cane sugar, you’d probably have to go to what is now known as Little Mexico. It was Sunnyside, a suburb of Winston-Salem, when my mother grew up there. I don’t recall seeing them elsewhere.
Maybe I should take a stroll down the international aisle of a few groceries specializing in unusual seasonings, foods and beverages from other countries to see if they’re there. We don’t really have too many “bodegas” here, not yet at least. That sounds like where they would be for most places.
We always keep a few bottles of "Mexicoke" in the fridge for when wifey makes popcorn.....just like bein' at the movies as kids. It's got that good old tanginess to it.