Yes, that’s simple.
Almost essential, but more difficult to arrange, is a means for openHAB to monitor the on/off state of the lights. You’re really restricted in this kind of setup if openHAB does not know if lights are on or off.
There are a few existing threads on various DIY ways to do this, example
Maybe, but you will probably want to retain the existing wallswitches which adds some limitations of choice.
Look at Shelley products, for an example.
