Have the same issue. Can lock and unlock the door, but can’t open it through Home Assistant. App works perfectly fine, it’s just Home Assistant doesn’t know the “open” state for the lock… yet?
As for today opening the door/lock with HomeAssistant is not possible,but the linked PR is heading in the right direction.
As for the other question with the german Linus L2 Variant it is indeed possible to connect to wlan with the wlan from the smartlock, you dont need an extra bridge.