Honestly, you'll get out what you put in with this breed. I've never known the dog's living accommodations to make as much a difference as the way they are handled by their owner. It sounds like you have quite a bit thought out, and I'm always glad to see someone doing their research before getting a dog.
I got my pup in my senior year of college, and we currently live in a 420 sq foot apartment. He does just fine because I make sure he gets the exercise and stimulation he needs to be happy.
I think you can do well with a dog in an apartment. And getting an older dog is a bit easier because they tend to be a bit less needy than very young puppies.