The response of Ayatullah Mahdi Hadavi Tehrani to all of the questions is as follows:

1- If a person was unaware of his bulugh (religious puberty) or the obligation of fasting at that time, or thought that he didn’t bear the strength to fast, even if this conception developed as a result of what those around him would tell him, then deliberate breaking of the fast will only entail qada (making up for the missed fasts). However, if in all of these cases, he knew that there are chances that he has become baligh or that fasting has become mandatory for him, or that he bears the strength to do so and it was possible for him to confirm the matter and to become certain or sure, and it turns out that it was indeed so, then he must also give kaffarah as a precaution (ihtiyat) as well.

2- He must make up for the missed prayers.

3- The sweat of the junub is pak (not najis) in all cases (if he became junub through halal or haram means).

4- Religious puberty (bulugh) takes place in two ways: 1- Physiological puberty which is the growth of coarse hair in the pubic area and/or ejaculation (ihtilam). 2- After 15 lunar years have passed; this is a sign even if none of the other signs happen.

5- It is pak and doesn’t invalidate one’s wudu or ghusl.

6- The answer to this has already been explained in the responses to questions one and two; the prayers and fasts must be made up for, and if the person’s ignorance was due to negligence and carelessness, he must also give/do kaffarah as a precaution.

7- He is apparently baligh and must make up for the missed prayers and fasts according to what was mentioned in responses one and two.

8- You must only make up for the number of prayers you are sure you missed.

9- Yes. Of course, referring to the signs is only for when you are not sure whether the excretion is semen or not. But if one is sure what was excreted was indeed semen, he will be junub, and if he is sure it wasn’t semen, he won't be.

10- No, there is no embarrassment in janabah, he has to perform ghusl.

11- No, it is totally natural.

12- The obligation of performing ghusl after the discharge of semen and the necessity to perform wudu to pray for one who has urinated has nothing to do with the najasah of the body. It is because of this that in regard to urine, although the urinary organ has become najis, the individual must perform wudu for prayer, while there is no washing of that organ in wudu. This shows that wudu has nothing to do with the najasah of the urinary organ and its washing, or else, washing that part would also have to be a part of wudu. These are matters we just have to accept that Allah has obliged us to do without question. For prayer, the body and clothes must be pak (tahir), and this allows one to be able to pray with wudu or ghusl. Of course, some hadiths state that the reason for washing the whole body in ghusl is because the whole body takes pleasure during seminal discharge. Nonetheless, this is only a hikmah (one of the wisdoms behind it) that the hadiths are expressing, and not the entire reasoning and cause for such, therefore, if someone wakes up and becomes sure that semen has been discharged, even if he didn’t feel it while asleep, he still has to perform the ghusl (and not feeling any pleasure won't be a justification for not performing it).