As you sadly found rocking and nursing don't teach a baby self-soothing techniques. I'll bet he's tired during the day, he more than likely isn't getting adequate REM deep sleep at night.
It sounds like you have several issues working at once, but the first to tackle is his being able to sleep through the night. Read this article, I read it earlier tonight, and hopefully it will give you ideas to use. I don't say "try" because you have to commit to something and not stop, just tweak, until you get the desired results. At 15 months there's no need to nurse him throughout the night, particularly if you are planning on weaning. The plan presented in the article should help with the sleep problem, if you stick to it, nothing works if you don't.
http://www.parents.com/baby/sleep/issues/advice/?page=1
Stop with the baby food and just feed him real cut up food at this age, he should have the finger dexterity to pick it up and get it to his mouth, and the jaw strength to gnaw, chew and swallow. After a year his main nutrition should be coming from solids, not breast feeding (and I nursed my eldest until he was three so I'm not anti-breast feeding.)
Give him Motrin at the first sign of teething discomfort, the longer you wait the longer it takes to go to work because the pain has set in. Make him some frozen fruit pops (fruit in the blender with some water, juice or yogurt and poured into Dixie cups with one of his spoons in it for him to hold onto it) and offer him one when his gums are hurting to cool them and ease his pain.
Darken his room so he has a dark place for naps and sleeping through the night. If you haven't structure a bedtime routine with bath, a story, nursing, and keep the lights low and talk in a whisper to relax him. And when you know all his needs have been met allow him to cry, he continues because he knows you will come, so send Dad to do his thing. It's good that he doesn't pick him up, that's what's keeping him from sleeping, being picked up. When you go in there, leave the light off, don't speak, say "shhhhh" pat his back and don't pick him up. You're not doing him a disservice by allowing him to cry, crying IS his way of telling you something, right now it's that he won't stop crying until you come and pick him up, not that he's in dire straights. Continue to do so and he will learn, if he hasn't already, that he'll get what he wants by crying :-/
And, co-sleeping now when you haven't done it before is asking for problems for years, you'd be trading one problem for another major one down the road. Read the article and stick to your plan, and wear earphones and listen to loud music. Oh, and if you even think he's going to try and climb out of the crib childproof his room and put his mattress on the floor before he falls out and breaks a limb or worse.