I am very new to the .223 world. I have purchased a short barrel bushmaster with a 1/9 twist for home defense. I have read through all the old posts about the best ammo for defense, and just seem to be more confused now than when I started. I think after reading through everything I have chosen Black Hills 68 grain ammo for my purpose. My questions is, is this an adequate defense round, and should I only load my mags for defense with the new manufactured stuff or is the blue box remanufactured stuff just as good?

Reman is once fired LC brass and unsealed primer.  Id try the 75 grain too and see which is more accurate in your rifle.  Yes that is one of the best choices you could make for defensive ammo.