well assuming this isnt a troll and your looking for a sincere answer..here is mine.
ultimatley the level or religiousity has to do with what the home life is like. If the home is filled with the love of torah and a proper life style, then there is no reason an arangement like this could not work.
However, there are two issues
1: The Morah or Rebbe would need to be up to snuff and be able to either match or exceed the limudey kodesh subjects so if the kids do transition into a jewish school they will either be on par or better yet ahead of the game.
2: Assuming you havent been shunned for doing whats best for your family, make sure they are exposed to a religious peer group so they can integrate well and not be dependant on their public school classmates for social interaction.
At that age – (Kindergarden to 3rd grade) there really isnt anything to objectionable being taught in public school so all you would really need to do is make sure the child understands that they are special and different and holy.
Just my opinion having made it through over twelve years of Jewish education.