I wanted to know, once stabilization is finished and we are at maintenance, must we still eat ALL the portions and foods on our plan? Meaning, if we don't eat all the recommended portions at this stage, will our weight fluctuate?

Well, in maintenance, it is more what works for you. Most people do continue eating all the healthy food, and I do believe that they do better. Afterall if you are filling up on fruits and veggies you are not eating the junk. The first thing they do in stabilization is give you unlimited veggies, so you can have as many (or as few) as you would like. Of course if you eat badly, your weight can and will go up... LAWL does not have magic fairy dust to make the weight stay off, so not following plan usually does cause people to eat more calories and gain. When you do gain (since I'm pretty sure everyone's weight fluctuates) you can cut out the bars to get back to goal, or go back to weight loss portions. Normally you add 1 fruit, 1 starch, 1 dairy, and 2 fats and possibly 1/2 of a protein depending on which plan you ended up at goal at. Normally you might drop down a plan or two during weight loss, so this may not be as much additional food as you are thinking.

In maintenance the food diary was optional.... So no one is really tracking your portions so much.

Eventually you do have to make your lifestyle changes your own and fit this plan or its close variation into your life.