Replacing hardwired smoke detectors with wireless. Electrical question

Hello

I have old (10+ years) interconnected FireX smoke alarms throughout my house. They have all been intermittedly chirping despite replacing batteries in all of them. Its also varying by which one chirps, telling me they are probably end of their life.

I'm looking into getting wireless smoke detectors that have the battery built in so I dont have to mess with it.

Question: Since ill be basically putting the wireless over the hardwired, what can I do with with the wiring so that there isn't live wires hanging behind the wireless detectors? Anything I should consider?

The other problem is that the breaker doesn't have anything labeled for the alarm, so I fear that each alarm is on the electrical circuit for that particular room, which is a PITA.