Hi;
We have a 15 week EM that we brought home 6 weeks ago. He is actually really good on the leash at this point (although he has his moments, he is still a baby). When we first brought him home he wasn't really interested in the leash either. He didn't fight, but like you say was just as likely to lay down and refuse to go. Time and patience have worked wonders. But.... the one thing that REALLY works well when he lies down and doesn't want to move now... we pull the leash taught (but not pulling) and turn our back on him. Sometimes it takes a while, but he is getting the point that if he stops he gets ignored, which he hates so the incidents of laying down and refusing to move are getting fewer and fewer.
As for the humping... mostly he limits it to "Bad Teddy" but there was once when he tried for my husbands arm. He got pushed off and told "NO". Others who have had EM's longer (this is our first EM, our past has been with dobermans, labs, and mixed breeds) please correct me if I am wrong, but I think this is a natural puppy thing and not necessarily anything to do with dominence, as there is no doubt in our house that my husband is the Alpha.
Hope this helps a little.