I have never played with custom properties, let alone know how to implement them. Please understand that I am an LC newbie who came from a HyperCard background (kind of dates it doesn't it? LOL).
Almost every helper on this list came from HC. I thought I was the oldest. I am not.
The short experiment I mentioned will take you ten minutes, and then you will be an expert. I assume you know how to set a custom property, even if you never have.
1- "set the changeColor of btn 1 to "true". Yep, this is all you need, and no different than setting any other property. But like a variable, it is both created and loaded on the fly.
2- In the property inspector of a control, choose the "custom" pane, add the property ("add new element") and set its value. Again, pretty much like any other property.
Craig