Have you heard of "Nothing in Life in Free?" A lot of people have used it on here successfully, you can google it. It's basically exactly what it says: NOTHING comes free to him. Do you free feed? Usually, I would suggest free feeding but with a food agressive dog I would not. Make him SIT before every meal. Let him know that you own the food, not him. Put your hands all in his food before you give it to him so that you're scent is in it. You should be able to take that food bowl away from him easily without a fight. For example, make him sit, give him the food and if he doesn't eat it within 30 minutes, take it away. Put it back down an hour later. He will learn you have the power. Just continue practicing these little things.
I would continue using the Coke can if it shuts him up. I know it's worked greatly for Jackson and he doesn't fear me in any way. He KNOWS when I want him to shut up. Barking at unknown things doesn't bother me (strangers, weird noises, etc) as LONG as when I tell him it's OK and to be quiet, he's quiet! So, if I were you and it's working so far.. I would definitely continue using the pennies in a can. Be consistant with it. Have a few cans laying around at easy reach. When I bring Jackson to my dad's house, my dad owns a Jack russell mix who is a huge barker and it makes me so proud when their dog just won't shut up but Jackson immediately comes over to me all quiet. So, I will give him a treat. Use his absolute favorite thing when he's quiet. He will learn eventually that is what you want him to do. You could also try a squirt bottle with water. I've used that whenever Jackson barks at the cats over at my dads house and he hates it so he stops.
As for the seperation anxiety, let him know you're always going to come back, you're not leaving him. Start slow. Pick up your keys and your purse and maybe carry them around the house but don't leave. He probably picks up little things like that and knows you're going to leave. So let him know it's not a huge deal, and jut desensitise him to your keys, your purse, etc things you grab when you leave. Then walk out the door, come back 3 minutes later, walk out the door, come back 10 mins later, make it longer and longer and keep practicing. Does he stay in a crate or in a pen or a small room? He probably should be confined if he is chewing, or having accidents, but I dunno if he is or not. Also do not make it a big deal when you come home or leave. Literally no byes, no hi's, just walk out the door calmly as if it's no big deal.
I agree with posters above... he needs at least an hours worth of walks a day on a leash. It really tires them out with new smells, etc. It just will tire him out. He sounds like a highly energic dog who needs rehabilition and I think you can do it
Any other questions, just ask us here at YT!