The problem with sitting by the table while you eat is that he is begging. He has obviously been rewarded at some point for sitting and waiting by the table, even if unintentionally. So when he thinks that he is doing something that earns a treat, but isn't getting the treat, he will up the ante. From sitting, to staring, to barking. Obviously the barking has earned him attention (reward, reinforcement), so that is where he progresses to quickly. The break the cycle, you have to stop the cycle from occurring, and the cycle starts when he is near the table to begin with. So by asking him to DO something that requires him to be away from the table, then you are preventing the cycle from starting that leads to his barking.
As for leashing him in a corner when he does something wrong, that isn't going to work. "Time outs" work for kids, but dogs don't think the same way. So leashing him in a corner is only going to build the association that his leash is a bad thing, something that goes on when you are upset at him. Instead of giving a time out as a punishment, give him something to do BEFORE he jumps/snaps that will prevent him from doing that action. So you need to have really good timing, and if you see him building to a state where he would normally jump, then give him a command to do something that will prevent him from jumping, something like "sit" or "down". Then praise when he chooses to do that action instead of the action that you don't want (jumping, snapping).
The jumping and pulling at your pants is not a sign of aggression, it is a sign of excitement and an indication that he has not been shown an appropriate way of venting that excitement. It will not likely go away as he ages, only get worse. So you will want to get on top of it now and show him an appropriate way of being excited or getting your attention. Stop reacting to the bad behavior, provide him something appropriate to do when he wants your attention, and only reward the desired behavior.
As for leashing him in a corner when he does something wrong, that isn't going to work. "Time outs" work for kids, but dogs don't think the same way. So leashing him in a corner is only going to build the association that his leash is a bad thing, something that goes on when you are upset at him. Instead of giving a time out as a punishment, give him something to do BEFORE he jumps/snaps that will prevent him from doing that action. So you need to have really good timing, and if you see him building to a state where he would normally jump, then give him a command to do something that will prevent him from jumping, something like "sit" or "down". Then praise when he chooses to do that action instead of the action that you don't want (jumping, snapping).
The jumping and pulling at your pants is not a sign of aggression, it is a sign of excitement and an indication that he has not been shown an appropriate way of venting that excitement. It will not likely go away as he ages, only get worse. So you will want to get on top of it now and show him an appropriate way of being excited or getting your attention. Stop reacting to the bad behavior, provide him something appropriate to do when he wants your attention, and only reward the desired behavior.
I know thats what mine would be. 