I'm sorry you think my opinion smells like poo-poo. I guess that's a fairly natural reaction to such blunt words. I see that you're married to this project, and I understand that -- I've been there. So, I'll discontinue with my advice to scrap the project and start a different one. If I can explain where my advice is coming from, perhaps I can convince you of something less drastic than starting over.
I know you never called your director an a-hole. But the way you described him in your other thread, he sure does sound like one. If the producer (the boss) comes to the director (his subordinate) and asks to go over blocking, and the director responds by saying, "The director does that", yep, that director is an asshole. Communication is arguably a director's most important skill, and he seems to be seriously lacking in that department.
You say that he is a great director, but what are you basing that on? He's never directed a film! Directing theater and directing film are NOT the same thing. Of course there's cross-over, as far as working with actors is concerned, but there's a whole lot more to it than that. He might turn out to be a great director, but he is not one. He is a rookie director.
You are a rookie producer. So your #1 and #2 people in charge are rookies, making a feature film. Some people might say you should hone your skills by making a few shorts, first. And by some people, I mean myself and almost every other filmmaker I know. If your first project is to be a feature, fine, so long as the only reason you're doing it is for the experience/fun/learning.
Knowing all of that, I chose not to say anything, especially since I know full well what it's like to make a movie that goes against the odds. But when I learned that your lead actor is to be a child, that was just too much for me to stay silent. I don't think you realize how much more difficult this is going to make shooting your film. I hope you've budgeted a WHOLE bunch of time for shooting.
So, my revised piece of advice is this -- you should at least consider the possibility of re-writing that lead character as a plucky teenager, then cast a young-looking college freshman. Seriously, this would make things SO much easier for you.
You've already got a lot on your plate -- much more than you now realize. Why confound it with a child actor? I think your odds of success will be much greater with an older actor/actress.