It seems that you are after exactly what I want. Initially I came here looking for a way of quickly configuring a large number of flic buttons on the hub via my desktop. But your other solution of configuring the hub with one url that then passes button name and action (either through url params or with a push request and a bit of json) would be great.
At the moment I have 3 raspberry Pi 3 dotted around the house. They all run the linux flic daemon and have node red running to actually do the action. There is a flic node-red node that make configuring this stuff really easy.
Lately however I have been having to reboot my pi frequently as for some reasons the flic button daemon stops working (it has been fine for about a year).
My proposal is to have hub that connects to all the buttons that will hopefully be more stable. Each button will then just call a url on node red that will then handle the request.
One of my use cases is that I want a flic button to toggle all the lights and wemo devices in a living room based on the state of one of the lights. You can toggle in the flic app but not toggle a wemo based on the current state of a hue light for example. This is very easy in node-red.