American "Bacon Roll" - what is it?
I have no clue what a "bacon roll" is... and if I had to imagine what it is, it would not be what you got. My mental image was a "sausage roll" but with bacon. 

A sausage roll is like a pinwheel or "cinnamon roll" but with savory biscuit dough (American biscuit) and ground sausage meat:


(Image from here)

So, a "bacon roll" in my head is the same thing but with chopped bacon instead of sausage.

I can find no reference to what you've described... which sounds like a bacon omelet. It's completely possible that you confused the waitress with your fancy British accent and she thought that a "roll" was British for "omelet"... though how she turned "sandwich" into "roll" and then into "omelet", I'm not sure.

If you want a "bacon sandwich" in future (meaning a roll with bacon on it), you might try asking for a "BLT - with no lettuce or tomato".... though, you should be sure to remember that our "bacon" is what you Brits call "streaky bacon", I believe. The closest thing we have to British bacon is "Canadian Bacon" or simply "ham".



As to the potatoes, they were likely what are often called "home fries". Roughly chopped/diced potatoes, sometimes mixed with peppers and/or onions.

Here's an image of "Cajun home fries", which look a lot like what you've described: