Does electrical need to be updated to hardwire in smoke detectors?
Yes you can. My wife has a Sunfire with both power and manual locks. Go to a junk yard and pull the parts off the same model. Be careful with the wires, they can be a pain.
To keep smoke out of smoke detector, cover with plastic Tupperware bowl, and wedge a long broomstick between it and the floor. Remember this is only for test purposes only.