Waht a darling!!
Just viewed Wilson's pics and he is absolutely adorable!! With regards to the leash training - I had trouble with all my dogs at first, but they soon got the hang of it. I agree with the others - let him get used to wearing it in the apartment, and let him lead you as he explores. Then try taking the lead a little bit each day. Sounds like you are doing a great job with the house training. The most important thing is to be consistent and watch for his cues telling you that he has to go out. Enjoy your new baby - Cathy