Dog issues, very confused

[Kassie94]

I hope this is the right place for this. I have a mutt and I have no idea of his age or what's in him except Corgi and maybe Jack Russell? But he has German Shepard markings and he's too big to be a Corjack but too small to be a Corgi Shepard. Anyway, on to the problem. When we first got him he I had no idea he had a problem with dogs until he attacked someone's dog in my neighborhood, FORTUNETLY I caught him before anything could happen, But since we moved (3 years now) he's been VERY strange. He approaches dogs but he's still VERY aggressive except with this poodle in our neighborhood, He also marks EVERYTHING in his sight including feet, boxes, chairs, anything. He's very rude when people come over. He begs for food and he tries to steal it out of guests hands no matter what I do. He will not obey me but he knows I'm alpha but he's challenging me. It has gotten to the point where if he does not get his way he bites me, nips me, anything really. He's very rough if I don't pet him right away and its worrying me now because he's broken skin and when I've said to stop and get down he just gets worse. He gets plenty of attention and lots of love. I run him daily for a few hours, I feed him and give him fresh water everyday, I've trained him to sit, lay down, and stay. I've done the stare test where If he looks in my eyes to intensify my stare and he looks away but he always looks right back immediately after. I honestly don't know what to do. My dad cant help because he's busy but my dog has gotten so disobedient that when he gets out he goes and runs away. He also only listens to my dad, like if my dad says go lay down or go away while we're eating he obeys but when I do it he sits right there and keeps staring at my food. I've kicked him off my bed as I have found It is suppose to work but any additional help on fixing anything would be fantastic. He's neutered too so I have no idea why he marks everything. I'm just very confused and need help with someone who has experience because I love my dog more than anything and would never do anything to hurt him but I don't like having to scold him all the time for peeing, or eating food out of my friends hands, for peeing on a guests suit case or even their shoes, or worse, getting in trouble for attacking a dog. He's even scratched and bit my face. If I don't give him what I want when I'm sitting on the floor with him he jumps into my face. I have scars all over from him. Please any help would be VERY appreciated.