Yes, I actually bred and showed great danes for 10+ years and was very thoughtful and analytical about pedigrees and history of my dogs. One of them died and I was heartbroken and I got a call from a friend of the manager of the norfolk pound who was looking for a special person to adopt a cute little street urchin who had been living outside for an unknown amount of time and had 0 known history. I was a little worried because of how much thought I had put into socializing puppies and knowing their backgrounds but I will tell you he is just the bomb diggity. Look at this dignified boy: https://www.instagram.com/p/B3zWIshhcj3/

He was definitely significantly older than we all guessed, just so underweight he looked like a puppy but really was just starved. He has some health issues that maybe could have been prevented by more thoughtful breeding (embark suggests his parents were full siblings) but overall 10/10 street gremlin adoption experience, would snatch a stinky wrinkle baby out of jain again.

Any new dog you won't know whether they are going to be good with cats until you figure out if they will be good with cats. I think you can probably get a decent idea by just meeting them and gauging the overall energy level, prey drive with maybe a flirt pole or something, etc.