general pet peeve of mine in What If scenarios where Kira lives and goes back to living a normal life is having him get back to being Kira and not Kosaku by killing Shinobu. don’t get me wrong. he’d probably be back to get her hands. but dude is undercover as her husband, and if he kills Shinobu he’d have to kill Hayato too. and THAT would attract attention. An entire family goes missing AND he still has Kosaku’s face? they’d be onto him in no time.
Kira’s actually fond of taking care of situations with as little death-causing as possible (re: Shigechi and the Great Sandwich Caper–he only took option Blow the Kid Up when Shigechi laid eyes upon the hand in question).
so i mean
he’d probably divorce Shinobu (the only conspicuous action he’d be willing to go through), go incognito and change his identity again, work his way back to reclaiming his identity as Kira, and then when enough time has passed, sneak in and Catch Those Hands