I made up 6 buckets like what your doing. I put Gamma seal lids on the buckets. I tried to think of simple meal plans and listed them out on paper to put in the bucket as well. I also added instructions on how to use things like beans and rice etc... that are not commercially packaged. You would be surprised the people who have no idea how to cook from scratch with simple things as beans.
Some of the items in put in are: Instant oatmeal packets of different flavors, sugar, salt, pepper, pasta packets such as Knorr & Bear Creek brands ( just boil water, done in 5 minutes), mac n cheese boxes, Hungry Man dehydrated hashbrowns in a box, DAK can ham, bouillon cubes for soup, spaghetti makings (pasta & tomato paste & seasoning packet) plus the beans and rice as you mentioned. With the beans I can add bouillon cubes and the canned ham and any vegies I can scrounge up and I have a soup. The biggest down fall is the need for water for cooking. I figure I can get water. I like the fact I can either use the bucket of food or give it to someone in need and it will feed them a variety for several days. I also stick in non-food items: roll of TP in zip lock bag, lighter, 50 rd box 22lr ammo.
I try to find items that have at least a 2-3 year shelf life. I use the food as the expirations come close and replace the items as needed. I was not concerned with weight in making the buckets.