The Parent Resource Depot

Question:
Ok, so my father gave us a puppy almost exactly a year ago. He was a couple of months old, and well my family and I have always wanted a dog so we said yes. That was a pretty ignorant thing to do. He seemed to be very timid and I think the previous owner abused him as he is completely terrified of brooms (he runs away at the sight of one) and if you speak loudly or even try to pick him up he pees himself out of fear. We tried to train him to go on the pad, which he does, but if we let him into the bedroom he just pees and poops everywhere, we’ve said maybe it’s because the floor is carpeted, so we no longer allow him inside unless he pees AND poops on his pad first. As of lately tho he’s been refusing to pee on his pad and pees and poops everywhere but his pad. We take him to walk but it’s just another horrible situation. He pulls everywhere, lunges off in different direction and barks at anyone who comes near us. He stops to pee on absolutely everything, but the barking is the most troublesome part as he barks at everyone including children who are outside (I live in a really lively neighborhood.) He refuses to eat ANY of his food. Just completely refuses. He will starve, then eat his food. We’ve tried every single brand that is out there and he just does not eat it. But he WILL jump up on the table and eat any food that is there, or when we are not looking eat the cat’s food (I have a cat, with whom he gets along well with.) Or when my baby sister is eating, he will go and take her food from out of her hands. He destroys the garbage to eat any food that’s in there so we need to hide all the garbage.
We don’t know what to do, and the only thing we can think of is giving him away because he’s just so unruly. Is it something we did? Because if I can fix what I am doing then I’ll certainly do it because I really want him in my life, but if he’s just not going to improve that I certainly can’t care for him. I know having a dog was a lot of work and I was ready to put it in, but now, I’m just really regretting it and considering never to get a dog again.
We usually feed him 3 times a day, soft food in the morning, a little hard food in the afternoon, and soft food at night. (But he refuses to eat it…) We usually walk him 3 times a week, should I change it to an everyday thing? He’s a mixed-breed (Yorkshire Terrier/ Miniature Poodle) So I’m not too sure on how much energy they have. What should I do about his behavior when I walk him? I let him into the living room and bedroom when he pees and poos on his pad as a reward but now he’s not peeing or pooing on it anymore! I’ve tried to clean the table and not leave any food in the kitchen so he does not eat anything, and removing the garbage so that he doesn’t get to that either. We don’t yell or hit him because I think that would really hurt the situation a lot more since he is so timid and that it’d be a step back, so I don’t know how to discipline him in an appropriate way, and one that doesn’t scare him. Ummm. We’ve taken him to a vet, and there was nothing wrong with him but that was a long time ago. I am going to be bringing him back. Does anyone have any advice on what to do?! I really don’t want to give up on him because I love him, but instead of bringing joy to my life he just adds stress. Or should I just give him up? I don’t want to, and neither does my family but we don’t know what to do anymore. We don’t have enough money for a trainer so that’s out of the question sadly :/. Any help at ALL would be appreciated.