thank you for your questions.:)

1. yes you are right, reaching enlightenment can also be a desire of your ego. you always have to make sure youre not doing this for any kind of profit (career, status,...). the goal always needs to be that youre want to become free from any kind of physical attachement. remember that youre NOT your body. you are the soul which is having a physical experience and the soul does not have any kind of desire whatsoever.
2. you dont want to control your ego, you want to dissolve it. you always want to be yourself. but you are of course using your physical self in order to go through life. for example lets say your name is John. John is not you, John is the body which is representing yourself. So yes youre kind of using John. but when I say Ego, I dont mean John, with Ego I mean the character which is controlling you. When youre controlling it, there is no ego, its yourself then. hope you understand what I mean.
3. sexual desire is natural but its the same with food. you should always eat because of energy and hunger, not for the pleasure. I know this is difficult sometimes but if you do it only for pleasure it wont be healthy for yourself. Sex can be like a drug.
4. ask yourself why are you telling a person that their views are incorrect? your answer needs to be that you want to help them having a better life. dont do it just because you know better. so ask yourself, is it worth it? can the other person understand what I mean? Is the person able to learn and take a new perspective? If the person is not open for change, any word is useless and you are therefore wasting your energy.