It is recommended to use 16oz jars if you plan to add some toppings to your oats; the extra space lends for easier mixing. Sectioned containers can also be used, with the oats in one section & fruits in another.
Greek yogurt isn’t limited to plain. I’ve used Chobani Flip yogurts as substitutions for three days when I didn’t have plain yogurt, & used the dry ingredients as toppings.
My favorite toppings are dark chocolate almond butter, chopped strawberries, & a medley of nuts. I personally use 1/2 tbsp of honey depending on the toppings I plan to use; because of this, I prep & mix my overnight oats in 16oz jars rather than making it in a batch. Overnight oats with toppings like these are a great way to consume some protein, fiber, vitamins & minerals. It’s also great for gut & heart health.