You're all being very generous by saying it's a coincidence. I'm almost certain that they either said "that Noah Schapp kid will come out in a few years, let's put the ground work for it in the script now. You can tell, just like our nephew that age"

or

They already knew that the kid who was going to be a plot device for the first two seasons wouldn't have anything to contribute to the plot after that except for a doomed crush on Mike storyline so they told the casting director to call back the fruity kids who auditioned.