A few questions...

there are different ways. depends on how strict you want to be and how closely you want to follow a true ketogenic diet.
I do total carbs ONLY. Its been proven that fiber DOES impact insulin, etc, and the doctor that came up with the net carbs thing has rescinded and apologized.

for the others. Lemon juice is ok..just count the carbs in it. Watch the amounts, is all.
What are you using to test your ketones? Frankly, personally I just dont. i got a breath meter i check every once in a while. The pee sticks dont work. blood meters do, but who wants to prick themselves all the time, and the strips are expensive. Stay under 20 grams total carbs a day, keep your protein under 60 grams a day, and you can be pretty well assured you are in ketosis.

Cheating.....again up to you. but unfortunately even a little can cause you to go out of ketosis. Its been proven that having carbs AND high fat isnt a good thing for your health. the basis of keto is very low carb, moderate protein, and very high fat...you mess with that balance its not good. I'd say...if at all possible, JUST DONT. However, if you cave, forgive yourself and move on and do better the next time. Its a process...just do your best. I found that i liked feeling better much more than i liked eating carbs.

I apologize if this is covered somewhere else and I missed it. Can you tell me how you are figuring your carbs? I have seen several versions and none are the same. Some subtract fiber, some subtract half the fiber, and I've even seen where they add the fiber to the total. Is there a standard way of counting?

I'd say then if it doesn't throw you off the main track, and you get back into ketosis quickly, why not? It's a personal decision. My main concern would be one brownie would lead into two, into half a day, into the week going badly... you know what I'm getting at. If that's not a concern for you, and it doesn't affect you negatively, make the informed choice.

My carbs are normally less than 20-25... I don't think I can really get any lower... and that's NOT net carbs lol.

STARFISH -

In my opinion - 1) - lemon juice is acceptable for keto.
2) - lower your carbs to get in higher ketosis. but not necessary for fat/weight loss.
3) - it will put you back as many days as it takes to get back into ketosis. My theory is that it's not worth it. There are keto treats you can eat that won't negatively impact you at all. If you eat (XYZ) and it takes you a week to get back to where you were before you ate it - was it worth it? Only you can answer that question.

I looked through some of the topics but didn't see anything titled with my questions...

1. Is putting freshly squeezed lemon juice into my water acceptable for keto?

2. I'm in moderate (4.0 on the box's scale) ketosis... and have been for over a week... how do I get it higher?

3. I'm struggling with really wanting brownies and these chocolate chip peanut butter banana cookies that my daughter makes... if she makes some... and I have a few... is it going to severely impact my progress so far?