Happy ending for you and Ninja .
I have a similar lost pet story with my captive bred juvenile male eastern water skink Cheakie.
He jumped out of his 29L rearing tub one day when I was changing his water and putting some live insects in his feeder dish. Ended up on the floor and promptly disappeared under the big display cabinet before I could pick him back up , then spent a few days roaming about the house - often seen on the kitchen floor and top of lounge and on the carpet exploring but too fast to catch..
Then disappeared ( found his way outside) , and a week or so later was spotted a few times and allowed my wife and I under the back of the house and near the back steps.
Even let us get within a foot of him before retreating ( but never scurrying away ) so we started giving him a cricket or two or some mealworms each time we saw him (I suspected this skink was my lost pet as his markings looked very similar in photos ).
He then showed up under my aircon at the front of the house about 2 months after his escape , and was coaxed into a "trap" with some mealworms , and brought inside and given a very close examination when he'd been returned to his rearing tub.
Like you I compared the makings on the captured water skink's franks with photos of Cheakie's and I found them to be identical , he's been back with us since about 2 weeks before Xmas and very quickly settled back into his old routine and if anything now seems much tamer and settled ( maybe just older ) and has been thriving and appears to be a very contented skink..
He and my two captive bred adult females will soon be moving into a 1200mm L x 596mm W x 400mm T home made tank to establish a colony .
He's now as big as my two adult girls who have been living in a converted 120L tub for a few years now and get on wonderfully with each other..
Yes as a precaution I'll partition off one half from the other with a removeable sheet of 6mm clear acrylic ( installed in some aluminium channel ) , he'll get one side , the two girls will go in the other side and I'll see how they respond to his presence before removing the partition.
I'm hoping the two older females will be OK with his presence , but if not , I'll replace the clear acrylic partition with some white coloured acrylic and only allow the group to mix in spring.