The best thing to do if it doesn't happen to work out with the new puppy is for all of you to go to the humane society together and bring Noba.
That way ya'll can meet the new dog and so can he. You can let the dogs meet on neutral territory to see how they get along and if Noba likes the dog there, chances are he will like it at home as well.
In other words, there won't be another chance of you having to return the new dog.

I also agree with what others have said. I would go for an older dog rather than a puppy. One that is no longer in the puppy stage at all.