RukiRG it's definitely a reasonable possibility.
But I wonder why DPC didn't work a bit more on Daz3D's shape and morph controls to eliminate such confusions. Why actually worked. It would be done in a jiffy.
But there are clues in the game. In the Lynette flashback in EP8, Neil asks Luis if he remembers the girl from a year ago. Neil was about 24 years old at the time. Rusty's mother about 22. Like now. How does he know that? Hahaha.
In the intro of EP5, when Rusty meets Jill, he is standing next to a picture. This picture shows a red-haired woman. Okay, the clue is still weak. But it continues. At EP5's prep party, after the MC talks to Riona on the porch, he is able to click on a picture that shows this very woman. He wonders how old this beautiful woman is. Now the MC finds the preps clothes and gets the two numbers for the cell phone safe. 42.
He MC wonders how old this woman is and gets the answer a little later. Now if we subtract the MC's age and Lynette's one year of pregnancy, we get 22. This woman was 22 when Neil (24) met Lynette (18). Neil asks Luis if he remembers the girl he had a year ago. So this woman may have already given birth to a little Rusty, who could be about 3 months old. And why? Pregnancy doesn't last 12 months. So we don't know when Neil will impregnate Lynette. So, I can only expect 9 months. That would definitely make the Rusty 12 months older than the MC. But Lynette and Neil still have some time. Then the age's difference could fit.
So I'll summarize. Neil has some resemblance to Rusty. Neil had a girl a year before Lynette. That girl was then 21 at the time and Neil was 23. Nineteen years later, an 18-19 year old Rusty stands next to a picture of a redheaded woman and makes a pass at Jill. Another two years later, an MC (18) clicks on that picture and wonders how old this beauty is and a little later gets the number 42. No wonder I'm starting to think that way.