I would not recommend you to get another dog just to deal with issues of eating and food. I actually think this might be the worst reason for getting a second dog that I've ever heard. I also agree with you that you should not have to force-feed him, and would discontinue the Nutrical as someone else suggested. He's large enough and old enough now that it's time for him to be able to eat food.
I agree with the other posters that there may have been too much variety given and that pulling back to just one or two food sources would be best. I do feed my older dog raw but I have had him for 6 years and I can read him very well. I know what he looks like when underweight, when overweight, and when just right. I know what his normal level of energy is like and would be able to identify a dramatic change.
I want to say this without being offensive, as that is not my intention. But it sounds like maybe you were a little too exuberant with food choices at the beginning. The dog might not know what to expect in his food dish from one day to the next -- raw, cooked, tripe, kibble, cheese, treats, yogurt, carrots...? This may have created some pickiness, as was suggested. His thought may be, "Well, if I don't fancy what is in my bowl tonight, maybe she will get desperate and something even better will be there tomorrow!"
I agree with the other recommendations. Select a high-quality puppy kibble. Feed that (and only that) for a few months. Train your dog to accept the food that he is offered, and don't be derailed by his "pickiness."
Your dog must learn that you can be consistent and that you have what it takes to be calmly in charge. You know more than he does. Panicking, getting angry, and offering him inconsistent choices sends the message that you do not have what it takes to be in charge. A dog may pick up on those vibes and it will impact your relationship in other areas.
this is terribly frustrating and sometimes, I really get mad. <snip> He is supposed to be at three meals a day now, he wont even have one
Please stop getting mad at your dog. He is not trying to make you angry. He is just responding to messages you are sending which, from the way you describe them, sound confusing. You have mentioned at other times that his other behaviors also make you frustrated. You then get frustrated by the people who respond to your questions and try to help. All of this could lead to stress for your dog who is just a puppy and trying to figure things out. Hang in there with him and with us.
Again, not trying to inflame. Just commenting on what I've read. You ask a lot of questions, which is good. But, it's confusing because you are often mad at the responses.