It's a telenovela, there are only hints. Mr Navarro being MC's dad Santiago is an obvious one: Gabi thinks you look like him, the bar scene is set up to highlight how similar you are.Guess I need to do another playthrough sooner than later I do not remember this but seen brought up a few times
Valeria being his daughter is based on how familiar she is with him on the track. Everyone is worried about getting an athletic scholarship and tries to get noticed by Mr Navarro, he actually talks to her first and she blows him off. Probably because she's closer to her mother, who he abandoned for a barely legal athlete that we now know as Gabi.