Aqara Hub AND Sonoff at the same time?

Suggest you instead read and follow these first:

You can have several Zigbee Coordinators/hubs/gatways/bridges to Home Assistant but you can not have several Zigbee Coordinator’s on the same Zigbee network or a device to more than one Zigbee Coordinator/network, so the Zigbee Coordinators/networks will not know about each other. Read the ZHA docs (especially the instruction and limitations sections) → Zigbee Home Automation - Home Assistant