usually for the the meal 2 and meal 4 (meal 1,3,5 is your usual breakfast lunch and dinner)

as per title.
goal is to loss fat while maintaining lean muscle

Well if you're on a diet which incorporates carbs, you need to remember than egg yolks have calories. At the end of the day it's calories in vs calories out which matter. Seems ok to me. If you find yourself putting on fat, then reduce the amount of egg yolks.

What is this 1 2 3 4 5?

I will stay away from eggs. You do have many choice of meat sandwish to choose from.

how about if me, do i eat only the whites and ignore the yellow? 168cm 50kg here ^^ im currently eating 3 egg breakfast, 3egg lunch, 6egg per day now, should i increase if i want to gain weight faster?

Add another 3 before bed.

Eat your yolks, they're good for you. And especially when you're trying to gain weight, you shouldn't skimp on the good stuff.