I think so long as you maintain consciousness that issue is fairly null in this particular circumstance. There’s lots of tolerance for changes in thought while maintaining the same self, see many brain damage victims. So long as there is minimal change in personality, there are lots of other circumstances that have a stronger case for killing one person and having a new person replace them due to change of consciousness, imo, I don’t think most people would consider a brain damaged person killed and replaced by a new consciousness, or a drug addiction with radically altered brain chemistry, etc.

I don’t see an issue with that. A prolonged brain surgery that meticulously replaces each part with a mechanical equivalent in sequence. Could probably remain conscious the whole time.