"mixed breed can temper some of the behaviors and also improve the dogs health by eliminating some breed specific health issues."
That is only possible if both sire & damm back at least two generations are all free of genetic health problems. It's another 1/2 truth that is floating around the mutt community.
Not to come across as sarcastic or caustic, but it has been well documented how "pure bred" dogs have become the way they are through inbreeding to isolate genetic traits. With that trait isolation has come a number of problems due to the homogenizing of the gene pool.