After making a flyer and putting it up, a fellow pet owner missing their own cat reached out and pointed me towards a building a couple buildings over. They told me they saw a cat similar to Mischief in the care of a friendly couple. Went over the next day and the couple instantly handed her over upon hearing she was missing and I was her owner. She's now back in the safety of our home and eating some well deserved soft food after her accidental adventure.
Thank you everybody! The couple that found him live in Building 1412. And they went all the way to the Irving Animal shelter. And I had just posted a lost and found at that shelter 5 minutes before they got there. So they called me and connected us so that I wouldn't have to pay the $150 impound fee. And they're bringing him over to the swimming pool as soon as they get back in about 5 minutes! They found him hiding under a bush by a vacant apartment next door to theirs, under a bush. - Edit - his chip still worked after 15 years! Who knew! Pic after his bath just now