Pillow and blanket should be provided for all international (and most redeye) flights. If it's not at your seat when you board, ask an F/A, they will have some stashed away in overhead bins. Both the pillow and blanket are fairly lightweight, you may want to consider bringing something of your own to supplement the onboard offerings if you're typically chilly onboard.
Delta's Economy Comfort food offerings are the same as standard coach (plus free booze). I've never had a *bad* meal, but they aren't gourmet. The options are typically a chicken/cream sauce/pasta option, or a simple pasta/vegetable option. Requesting a vegetarian meal will probably get you the same pasta dish served throughout the cabin, I'm not sure about Kosher. Personally I'd stick with the standard offerings (I find the standard chicken quite tasty), but I'll let someone else comment on the special meals.