hard to say, I'm on the fence
I have two aussies, one is a real marshmellow, her behaviors have never rubbed off on my gsd whom I got as a puppy when the aussie was 8 years old
If your interested in the rescue, could you try them out on say, a 2 week trial?? Option if it doesn't work out you could return them??
I might go that route, puppies are cute, but a real pain in the butt (maybe it's my old age LOL),,the older dog would be perfect if he is as they say..
Certainly up to you