OK so I switched to [RELEASE] Tasmota (Connect) for Sonoff, Tuya, SmartLife & other ESP8266 devices) earlier this year (and stopped using MQTT and a bridge).
I have around 12 sonoff mini (all flashed with tasmota); shelly devices (some flashed some not); ifan03 flashed with tasmota. All work perfectly. This software is by far the easiest way to controll the tasmota devices and the ifan03 is easy… I actually use both the ifan03 and a mini to control the lights… the mini isnt connected to smartthings but I use tasmota rules to share light settings between mini and ifan03. The ifan is not connected to the light, but is the switch in ST… this is just so I keep the setup simple and the light switches work the way I expect them to.