I think it's likely if that mom kept the baby for herself (as opposed to taking him for some gang leader she works for or for debt payment), he would be going by Jose Guadalupe, the name kidnapper stated she gave her baby.
Not sure if it was mentioned here already, but according to an article by Fox4now, the detective on the case believes the calls the kidnapper made while in the car to that "random" business were connected. "We feel as though there's a nexus between her making this telephone call to the pole shed," Iarossi said. "One of the people who actually stayed and lived at a house next to that pole shed — his name was Jose Guadalupe."
Since it's common, especially in latin american cultures, to name a son after his father, I think the kidnapper's baby woulda shared the name. Whether her actual baby boy died and she was looking to "replace" him by stealing a baby, or never existed in the first place, I think baby Bryan would have been raised as "Jose Guadalupe".
With that being said, I was able to find a few Jose Guadalupe (insert last name here) that live in that general area of Florida and turned 18 last November/December. All look pretty similar to the age progression (unfortunately I'm not good at comparing those though). I'm probably not allowed to share the names (or Instagram handles) here, but I hope the police have looked into those Jose's.
(Attached a screenshot of the news article I mentioned above as a source since I can't find it now but I did think to screenshot it at the time.)