Wow...what a roller coaster....so sad about the Chief...I know all too well the hardship of DM..watching such a regal creature being slowly compromised in the physical being is incredibly difficult.....but you did all you could and hung in there until the very end. That last "walk" in the vet's office is one which brings you to your knees...their eyes are still "clear" but their body just will not cooperate...it was the toughest of my three dogs to say goodbye to...I am sorry you had to go through this episode but glad you had the " Chief of all Dogs" to grace your lives. Your G'daughter Addi is a trooper and I'm sure your are so proud of her standing tall at such a heartbreaking moment in a young person's life.
A thought regarding the "good part"...first ...good for you for making the effort to acquire your new pup....second..Jazz Baby will never be Chief as you stated but I wouldn't be surprised a bit if from the "ashes" of Jazz Baby's first 5 months comes a dog which will be more than perhaps you are imagining...she may be damaged now...but with your love and caring ( which is evident ) Jazz Baby has nowhere to go but onward and upward.
Once again, so sorry about the Chief and your family's hardship watching how DM progresses but I'm happy you have a new project to work on, especially Jazzy Baby, who, if not for your actions would have had a crappy life and now has nothing but opportunity and love to look forward to....