BAHAHAHAHAAA! Table manners in a 2 year old! Two year olds are like little wild animals. Talking really doesn't do much. Here's my advice, having survived several two year olds.
1) Your son does not need to eat dinner with you at this age. Feed him early (like around 5) and put him to bed. Then you can have a nice, civilized dinner with your husband. Life is hard enough without having a little wild banshee at your dinner table.
2) If he throws his cup, oh well. It stays on the floor. If he throws his spoon, then no spoon for him. Not negotiable. He will not die of dehydration. Emily Post and Miss Manners will not show up on your doorstep to see if your 2 year old is eating with the correct fork.
3) Kindly tell your parents that if THEY would like to teach him to use a fork while he is at THEIR house, then they are more than welcome to play the fork pick-up game. That's a fun game for grandparents.
4) If he's going to put his feet on the table, put him in his high chair and move him away from the table.
Really, you can't expect decent table manners out of a child until they're 3-ish (and by "decent" I mean that food will not actually fly around the table, but they will still put Spaghetti-O's up their nose), and with some kids it's more like 5-ish. Especially when they're 2, they LOVE getting a rise out of their parents. Do not engage in this battle, it's not one you'll win. He is showing you that he is not old enough to sit at the table with the grown-ups. This is not a failure on his part or yours, he's just 2. Nobody ever went to college unable to use a fork. Hang in there.