The core idea behind the Green Faces plan is to make the diet so ridiculously simple that it's hard to screw up. Hence the straightforward "has a face or is green" concept.
It make things more simple if you pare things down, but you don't literally only have to eat those two categories. As far as seasonings, spices, dressings and whatnot, at the very least stick to a "no added calories" rule. I'd suggest just vinegar on salads (or lemon/lime juice like JFG said), but no oil. Since you do have fairly free rein in terms of eating fattier meats, there's no sense and no need to add more grams of fat on a vegetable dish.
Take whatever supps you normally take. The only recommendation is Plazma before and during workouts. For sure, it breaks the is green/has face rule but the improved workout quality and recovery is worth it. It's also a recurring source of carbs, removing the need for a dedicated carb-up day and allowing the diet to be followed longer without needing change.
Just like you don't literally have to follow "green stuff/things with faces", you don't literally have to follow "unlimited" amounts. Common sense is great. If you're the kind of person who can knock back a 32-oz steak and ask for seconds, then restrain yourself, Kobayashi.
I definitely wouldn't overly focus on lean meats, because your only real sources of calories are proteins and fats. But you can sort of wing it. Eat until you're mostly full (that's the old saying anyway. I'm still trying to figure out how that one works). Eating more vegetables in a day than most eat in a week is also going to help you feel full and will sort of autoregulate calories and hunger.
I don't remember reading or writing that. Outside of workout nutrition, there's absolutely no need for protein shakes during the day. Dairy is definitely a no-go.