I would like to crack about a dozen eggs and mix in omelette ingredients and store them in the refrigerator in an airtight container for a about 4 days for a faster breakfast. Is this safe?
It might be easier to freeze individual portions in zipperd freezer bags instead.
Lable the bags with the date and ingredients (Mushroom Omelet). Each bag should contain a couple eggs and whatever omelet ingredients you like. Zip it up with as little air left in the bag as possible. Mush up the eggs a bit so they are "scrambled a bit". Store in the freezer.
In the morning, cook the omelet by boiling it 10 minutes. Breakfast prep shouldn't take as long and it will free you from having to stand at the stove while the omelet cooks. Clean up should be easier too!