Macro Nutrients and What you Eat

Spyer116

How important is it to hit all your macro nutrients every day?
And does chocolate or other junk food make any difference in fat loss vs lean body mass loss, or just body fat percentage?

(i'm 20, 5'4, 149 pounds, male)
Daily calorie limit is 1270.

But yeah, almost every day, I seem to be short in hitting my macro nutrient goals, even if going slightly over the calorie limit. (I log walking and treadmill, and some other exercises. And do eat back maybe up to 20-50% of the calories burnt from exercises). I do take a super multi vitamin for the reasons that 1. I don't have too varied a diet, since there are plenty of things I don't like anyway. and 2. I'm eating at a good deficit, so also to help just prevent any deficiencies in vitamins or minerals.
Reading up alot on Clean Eating vs IIFYM, I personally find IIFYM the way better choice. But not on the ridiculous argument that I can just eat junkfood all day everyday, and hit the macronutrients. On almost a daily basis, I do save 100-200 cals for a little chocolate, or some other sweet food. And I drink no cal / no sugar sodas most days of the week too.
But if I'm eating relatively healthy for the majority of my calories. eating a little bit of sweet food most days (if not every day, and not hitting all my macronutrient goals set out by mfp, or going over some on some days, does any of that influence my weight loss negatively (fat vs lean body mass), or my health?
And i'm pretty active too, at least 1 hour each day of walking, sometimes 4+ hours, and strength training in the gym up to 4 times a week.
Because i've also noticed, on one or two days where I did eat only good foods, and no sweets/junk food, and low in fat foods, I still didn't get near to hitting half my macros.

And one last question, unrelated to the title. Fiber. How important is it to hit the fiber limits each day? Because just what i'm naturally eating and enjoying on a daily basis, I seem to get very little fiber. And don't go umm.. number 2 on a daily basis. It seems to be every 2-3 days, and only a little bit, even though I'm eating a good amount of food each day. I assume thats just because of low fiber, and everything is still ok?