You don’t need a apple router (not a apple person either) just add the homekit device integration, then in the stat enable HomeKit and set it up in home assistant.
As much as i’m not a apple person I really do like the homekit device integration, it finds devices that are homekit compatible automatically, being local its often faster than native cloud integrations.
The SmartSensors I’ve tried so far will pair with Ecobee 3 lite, 4, and premium stat’s, and once paired to the stat will show up as a device under the homekit entry for the stat.
The Smart contact sensors EBDWC01 expose contact, motion, and occupancy sensors as well as battery level but I’m not sure that value is valid (all my sensors always show 100%).
I’ve found many devices expose additional or different entities via the homekit integration than the native one which supliment the properties integrations natively support. E.g. the ecobee Smart room sensor EBERS41 in the ecobee integration only exposes occupancy and temperature, but in homekit exposes those as well as a motion sensor which has much faster response than occupancy (although it still seems to have a 3-5 min minimum)
