Lightweight, but not freeze-dried:
Take a look at the Fantastic Foods line in your nearest grocery store. All of their stuff is vegetarian and, IIRC, marked as Kosher. See if any of the couscous, bulgur, or other "instant" starches are also marked as vegetarian or Kosher, so you can add them as extenders. In the case of the FF soups, they do fairly well when thickened with some couscous, rice, or mashed potatoes, etc., as a meal. In a pinch, add crumbled matzo crackers.
If you are going with vegetarian foods, you won't have an issue with mixing meats and milk products, so you can supplement with cheese, when desired. If the people you are concerned with need Kosher certified dairy products, they will e more expensive, but should be something that you can locae.