Great rule of thumb to remember - a tired dog is a good dog. All of your problems will be easier to deal with if he is exercised a lot! Of course, you will still have to deal with the problems, too.

Pants? Never let him get to your pants. Just make sure they are out of his reach and give him something else to replace it (perhaps a ropey toy would be close enough to fabric?). Eventually he should forget the association of pants = yummy. Maybe. Maybe you'll just need to keep the pants away from him forever.

Stealing food may be tough. If he's anything like my beagle, you may be stuck with never leaving food where he can get it.

The leash-pulling may be the easiest to "fix", though it may not seem like it. He will need consistent, frequent training sessions. Look around on youtube for training videos, they should help. Mostly, you have to never let him pull. What I mean is if you are pulling on his leash to sort of hold him back, you are working at cross-purposes to your goals. Make sure that when you do a correction, it is followed by releasing all tension, he needs to get out of that habit of having tension on his neck being normal. There are great lead/collar things (I can't think of the name of this type, help someone? They attach sort of to the head rather than neck, and are supposed to help with pulling?) that may help.

This will be very frustrating! Remember it is not his fault, he was taught these things. Try your best to be patient with him. Also, someone else mentioned kong toys, that's a great idea if he is a toy-destroyer. Daily exercise should help with this too (although some remain toy-destroyers regardless of activity).