Update. My feral rescue is doing fine, being allowed to roam the house a bit more. Figured out the litter box but that was while he was confined to a small area. I'm giving him more freedom in the basement and we'll see how that goes.
It purrs like a 6 horse evinrude at idle. I'm trying to get the age from my ex father in law and we may never know exactly. He is guessing 6 months or maybe a bit older and checking with his wife. I was thinking younger so it will be interesting to see how big he/she gets.
It looks like the name will be Houdini given the whole escape and recapture routine we went through over the weekend.