I can sympathize. I've had roommates who never put anything back in the fridge in the same spot twice. It's a pain to have to hunt for the basics--eggs, butter, mayo--every single time you need them. It is just so much easier to put stuff back in the same place every time--you can find things so much more quickly.
Instead of specific places for each item to go, you might get more cooperation if you designated areas for certain types of food.
Growing up in a family of 10, some degree of order was necessary or we'd never find anything in the kitchen. We all knew which shelf on the fridge door held the salad dressings and ketchup. But we didn't always put the ketchup back in the exact same spot every time, just on the correct shelf. The cheese always went in the same drawer. Fruit was in the right bin; vegetables in the left bin. But other stuff, the random stuff purchased for the next few meals, might go anywhere on the bottom shelf.
So maybe start small. Identify 5 or 6 things that would make a difference to you if they were always in the same spot, so you could just reach in every morning, say, and get the cream for the coffee. Label those spots and ask for the cooperation of the other people in the house in keeping just those few things in the same place all the time. Listen for their input--they might have a suggestion for a better place to keep something.
Then, if they can manage those few important things, in a few months you can work on adding a few more to the list of "always in the same spot" foods.