>There's a reason the founding fathers all had slaves; they weren't the common folk.

Ah, yes. All Slaveholders. I once toured John Adam's former plantation. It's expansive. Really puts Monticello to shame.

(the joke here being that John Adams was a practicing lawyer in state that didn't even have slavery).

Super good joke.

Since your point seems to be that not all the founding fathers parent was referring to were actually slave owners do you have a claim for a rough ratio? I think that would be interesting and would be a more informative thing regardless of where on the scale it lands from "everybody but Adams" all the way up to "only a big names like Washington, Jefferson".

To a first order approximation half the founders were from New England (no slavery) and the other half were from Virginia (no realistic chance of being important/rich enough to be a signatory without owning slaves). So call it 50-50