From version 3.135 of EZ-GUI, cleanflight 1.8.0 is supported.
Remember that Bluetooth range is very limited. In the best conditions it can work up to 50-100 meters but it can also stop working after 10 meters. Setting the failsave is very good idea to avoid flyaways.
Phone call or message can bring EZ-GUI to background and you may lost control over your craft.
I bought CJMCU mini quad and I wanted to control it from my phone.
This is how I did it.
CJMCU is a cheap micro quad which runs cleanflight.
I used a Bluetooth and Android phone to control it.