You sound very thoughtful. I don't know if you'll be living at home until you are 30 yrs old, you may need or want to move for work and finding a place that will allow a dog is always uncertain, so is your family OK with caring for a GSD while you are gone?
Getting a new puppy could make your Cavalier feel like younger again and he may want to play, or it could go the other way where he is annoyed with a puppy.
If you read through here, you'll see there is not just one type of German Shepherd. There are Showlines and Working lines. The Showlines generally have a milder temperament, the working lines may be a bit of a challenge for the first 2 years.
GSDs are very loyal and would love to have someone home all day. You may want to ask your vet if he/she thinks the activity of having a new dog would be OK. I'm just curious as why you want a GSD? We have a very active Greyhound rescue in our area, they seem so sweet and nice, I almost took one home, but we are at our pet limit. So just curious why a GSD and not one of the other nice breeds you've fostered?
My Mom will be putting in around the same amount of input as me as it will be a son/daughter (although im hoping for it to be more my dog) effort so from that POV it wont be too bad if I need to spend a small amount of time away from home. (although there is my brother and father but they tend to take a back seat and we do all the work which we dont mind)
If I ever do move out, it will be more my dog than anyone elses as I will be the one taking to training, walking it, etc so Id move out with it assuming I could afford to provide for it (which I will do anything to be able as my chosen career path is my absolute passion so Il hopefully find a way to provide from it one way or another) although moving out really isnt looking plausible with the house price and financial situation of the UK in general! (Which is just as well as Im very close to my family)
As to others concern about them being attached to you, I couldnt love that more! I love fuss pots so its all good in that department.
Theres absolutely no shortage of interaction and fuss for dogs in our house
. I am very close to our current Cav and absolutely love him to bits. Theres nothing quite like a bond between yourself and a dog.
Also, the other breeds! We would have fail fostered most of them! At the time though, I was recovering from a breakdown and it was too much for me at the time to handle. (thats when I started home education, school was just terrible so I was home educated and have been so much better for it since. Both educationally and mentally)
Those particular breeds still arent off the list, same goes for Greyhounds. Always good to weigh up our options! I think we are more curious about GSDs because we have never owned one before and we know a lot of people around us who have who cant praise them enough (providing you give them the right training of corse) so we are quite curious.
The Labrador we fostered was a puppy (although he was a bit of a freak like that, he was totally not puppy like... Pretty calm as far as puppies go! Having said that he was a slightly older pup) and our cav got on ok with it. But if the puppy does get too much for him, he usually follows my mom and hopefully the GSD will be more my dog as mentioned above so Il hopefully be able to get him some peace if need be.
We have been looking at a few breeders and we have seen one that is KC registered (although I dont particularly agree with the KC due to their policies with cavalier health... So as far as KC goes, I dont care whether or not its KC registered) which has a good hip and shoulder score? I assume this means they are less likely to get hip problems which is the most common (?) health issue for a GSD? We wouldnt consider this particular breeder though as its come from a working dog background so that probably wouldnt be a good idea as we would prefer a show one. (which has a milder temperament like you mentioned) We have seen a few show ones which would be suitable as well. This isnt something we are planning on rushing into especially as its a new family member, we need to make sure we get it right and make sure its the right thing for our family.
Querying the vet would be a great idea as to how ours will cope. Lots of thinking to be done!
I used to keep fancy rats, and havent had any since my last one died because I was unsure of which breed we were going for next if we do. What are they like with smaller animals? Doesnt bother me either way but just curious