You own inner voice is telling you to wait; hence the ANXIETY.
I would wait (been here before) myself. The new puppy will be HELL.... on the elderly Husky. You will have REGRETS (if you rush to get the puppy) and have less time to spend with her, in her last moments & you want her exit time to be good, or as pleasant as possible - or you need to GO AHEAD and put her to sleep. She does NOT need harassment, from an unmannerly pup.
You will even have to put your male MIX aside (to some degree) to concentrate on the UNTRAINED hooligan puppy - if you CHOOSE to buy only a young one; not adopt a juvenile who is already housebroken an crate-trained from a GSD rescue program.
I am not against buying (some people are). I do know the value of buying (esp in such a popular breed as the GSD) from a reputable source - if you want a puppy from TITLED parents with multiple HEALTH SCREENINGS. I would NOT be getting a male puppy however, I would be getting a female. Opposite genders usually get along better.
Ahem, you do seem to think you are right, about walks and boredom. Sure, if you live in the "middle of NOWHERE" -and/or if you own a stubborn or "difficult" dog..... it REQUIRES some CREATIVITY. Have we run out of creative activities for our dog.... or just never thought OUTSIDE the BOX? <LOL> (Try having one of THE MOST active & smartest dogs on the planet......)
Put out some dog REALLY good, dog treats on your walk (ahead of time). You can try dog biscuits or soft dog jerky - but they are not really yummy - unlike cheese, hot dog, etc. But of course, some items...might "walk off" if you don't get OUT quickly after "planting" a few.
Now, once the dog figures OUT there are "suddenly" a few ITEMS to FIND on his walk... he will be enthused to GO, GO, Gooo......(if you use the right stuff).
And in the future, you might put the "goody" inside a folded-over glove, or in a folded sock, etc. WHY? 'Cause you can actually hide it better down in some grass or bushes - AND protect it at the same time! And the action is not UNLIKE beginning tracking.....where even a lame or cripple dog, can USE HIS NOSE, and his BRAIN and move at his OWN pace. (See also Nose Work games.)