I would like to give some suggestions regarding the food and hydration system.
First of all, I would like to begin with the food. Similar like in the game “Survive the nights”, there’s a feature where you actually physically have to cook food by putting it on a stove or cooking plate. it takes then some time to cook the food depending on what type of food. You could maybe also be able to cook canned food, which than gives more food/hydration.
It could also be nice to make some sort of “stew” of “soup” from various ingredients. Let’s say a bunch of different vegetables, and noodles would make a soup that gives a additional effects such as, heat, hydration and food, and the vegetables could affect your health, perhaps making you have more resistance.
Each food would have their own value of “calories”, the effectiveness of your food would be perpendicular with the calories. Certain ingredients combined would form a dish which gives additional effects, boosts and calories.
Now let’s talk about the hydration.
Certain foods would give additional hydration, foods like soup would give a significant bigger amount of hydration than for example canned food, dishes with vegetables would give a normal amount of hydration.
A interesting way of having a source of water, is by boiling salted or dirty water, this would only be possible with a cooking pot by putting it on a stove (which needs firewood and a lighter/matches to work)
Another interesting way of getting water, is by finding drinkable water for example from sinks in houses, water towers, bottled water, etc.
I hope these are some good suggestions, I my opinion their not too realistic but not too arcady aswell so they should blend in perfectly.