Sounds pretty reasonable.
Within the US, there are at least two major diner chains:
At a diner in America, I'd be unsurprised to see some less "diner" offerings. When I go to my local non-chain diner, I order fettucine alfredo. And the article here has a good picture of a diner advertising "American and Korean food". I think part of the core diner concept is a somewhat athematic menu that is meant to cater to local tastes.
With that in mind, Cheesecake Factory might also be thought of as a diner. https://www.thecheesecakefactory.com/menu
So I'm a little surprised at the idea of a diner that only has classic burgers / shakes / pancakes, but I'd have to admit those are fairly core dishes.
I'd say a waffle house is a better chain if you're in the lower Southeast. Much closer to a true diner experience
Yes, absolutely. They talk to you the way I expect to be talked to in a diner (lotsa “huns”), the coffee never ends, and sometimes you get to watch UFC live. The food is so easy to eat, too.