What works with openHAB you ask? Well this => Add-ons | openHAB
- Depends on the use case, Phillips Hue are expensive, IKEA Tradfri is good, without a gateway, why?
- Sonoff S26? Depends on the Firmware flashed, with Sonoff Tasmota it works via MQTT mqtt binding doc mqtt generic thing doc mqtt broker aka. Server
- Why IR? There good ones with Wifi, ZigBee, ZWave etc.
- TVs can be controlled via. IR and or HDMI readup
- The Sonoff SC is for measurements please read up on the product information
- again depends on what you want to do, some ZigBee setups come with a Gateway like Xiaomi
- Really dude? Common… read some docs… openHAB has so many bindings for use with so many devices… Add-ons | openHAB