The simplified forms of the functions are:
- \( q(x) = (x + 3)^2 \left( (x + 3)^2 - 3 \right) \)
- \( r(x) = x^4 - 3x^2 - 2 \)
- \( s(x) = \frac{x^4}{256} - \frac{3x^2}{16} \)
Thus, the final answers are:
\[
\boxed{q(x) = (x + 3)^2 \left( (x + 3)^2 - 3 \right), \quad r(x) = x^4 - 3x^2 - 2, \quad s(x) = \frac{x^4}{256} - \frac{3x^2}{16}}
\]