With the recent announcement that openHAB 3 will be released by the end of the year, switching to MQTT v2 will future proof you for a bit, so I think it’s worthwhile! Note that the bridge.things you’ve already created is now your connection to your MQTT broker - no need to create a new one for each new Thing! Just reference it when creating a new Thing, as shown in the example above.
Depending on your temperature and humidity sensors, this might be useful. If you get stuck, just start a new thread with what you’ve tried - people are only too happy to point out where you’ve gone wrong…! 
Pob lwc!