Just to clarify one thing
You are linking to my post which refers to the alpha version of Modbus binding for openHAB2. The major difference to the old binding (used here) is the introduction of things instead of cfg file configuration.
The old binding is the stable version, and yes, it works with openHAB2, similarly to many other bindings originally developed for openHAB1.
In this thread, some issues might occurr with Dimmer not updating… it’s weird that you did not have to do the “transformation trick” as described in the other thread.