@jeremushka I developed this device and added functionality to it that can be useful for many users of MySensors technology. Personally, I use only the lamp on / off function. I do not use the wall switch, current flow detecting, etc. I can only theoretically answer on your questions. For confirmation it, is necessary to implement all this in the sketch.
Do you detect in the firmware if the light is off or on with the ACS712 ?
It is possibility.
Does the push switch from the wall will still be acting independently of this Mysensors board?
Wall switch must connect directly to terminal block. No other connections should be.
Light status (on/off) will update when the physical switch will be pressed?
This needs to be controlled by the sketch.