What About CP(for axial capacity of stud). We cannot take it = 1 right?. We can only use minimum slenderness ratio and not the larger slender ness rayioon in our calcs for FCce or F'c.
Cp is usually the controlling modification factor for wood stud walls; it will typically be significantly smaller than 1.0. If it's approaching 1.0, you may want to consider increasing the economy of your design by using a smaller column (stud) section.
Since you are looking at bending of a stud wall, make sure to check the "Bending and Axial Compression" interaction equation (1995 NDS Section 3.9.2).
But, Cp=1.0 for weak-axis buckling. Don't use l/d for weak-axis in the column stability equation. Also, when doing the combined check, make sure to use the correct FcE (in the plane of buckling being considered - for your case it will be about the strong axis).