Your macro nutrients depend largely on your goals, and most importantly how your body personally uses the food. So what is it you are trying to accomplish with your diet? Just to be healthy? Get bigger? Be leaner? Get stronger?
I think, regardless of your goal, a gram per pound of lean pound of bodyweight is a good place to start. You can always adjust as time goes on.
No one fucking knows. Don't even let them try telling you. There is a study to back up every single theory on what is the best way to eat, and equally a study that disproves it.
You could try supplementing with a protein supplement if you have a hard time getting a lot of protein in your meals. 180g divided among 3 meals and two protein shakes is roughly 36g per meal. You could also experiment with four actual meals in your day as well.
If it is important to you, yes. It may be beneficial if you are not aware of what is in your food, and you don't really know how much you are consuming in your day.
Leafy greens, peppers, onions and such, are not important in your daily carb totals. The important things to count are sources like rice, potatoes, oats, fruit, etcetera.