You are absolutely right. Nutrition is a very complicated topic! Taste and feel are incredibly important as you mentioned. As for the legumes you are absolutely right about them causing you to be gassy! They are well known for that which is why we have a silly rhyme about it here in Canada.

Beans, beans the magical fruit. The more you eat the more you toot (fart) The more you toot the better you feel So lets eat beans for every meal

Now the farting is from bacteria fermenting the undigestible fibers in your gut. Helping to feed these beneficial bacteria with fiber is actually beneficial to the gut biome. Also these undigestable fibers are excellent in promoting proper bowel movements. Proper bowel movements help to eliminate waste but also help with things like preventing bowel cancer. Sure it can be embarassing to pass gas when you don't want to but nutrition wise it is hard to beat legumes.

Liver is an excellent source of vitamin A, vitamin D, and iron. It will get its time to shine when I'm looking at the best sources of each vitamin. Bones are excellent source of calcium and magnesium in soupss. Plus the gelatin they release adds texture and flavour to the soup as well.

Lung typically isn't sold in Canada. Intestines are but they are less common than regular beef.

At the end of the day I've just written about the 3 major macronutrients so far:
Carbohydrates, Fats, and Proteins. There are many more vitamins and minerals to go over the next year. The main goal in putting a price per 2000 calories on everything isn't to suggest eating only one type of food for minimum cost. Rather it is to provide a framework to tell whether something is expensive and cheap based on the nutrition it gives. Also looking at the types of nutrition in each food helps to determine how much of something you should be having.

Portion control is out of control here in North America. I have a refillable cup from 7/11 and they charge the same amount for a soda refill regardless of the size (mostly. They sell a 64oz cup (about 2 liters) which is often downed by an individual! That's a crazy amount of soda for one person in one day. Personally I fill it and divide into smaller containers for the whole family. When I was in the USA they had a 128oz container.....who could drink that much sugar? The same portion control problem is in many other products as well. I wanted to look at individual raw foodstuffs a little more closely so there can be a correlation between what you need and how much you need to get it.

How people put everything together in tasty recipes to improve taste and mouth feel is the magic that brings raw ingredients together :) But I'll be exploring that in my other account (Hive account@tergan) to find ways to take inexpensive ingredients and more expensive ingredients to provide tasty food that provides the nutrition you need. Again, early days for everything and I have a lot more to research but thank you for starting off the discussion!