Yes, in addition to silicon, you'll have to account for the geometry of the bond angles in the other atoms as well. Nitrogen is likewise a tetrahedron, it's just that one of the four bonds is represented by unpaired electrons. There's no reason to absolutely rule out your structure because of heteroatoms. Any crystal can have impurities, and still technically be the same crystal as if it were pure. Of course, just because something can be made, doesn't mean its stable enough at intermediate steps to allow it to be made. Also, there's the issue of if the molecule can even begin to be made, if you can't impart the energy needed at all without failure.