In Islamic law, najis (Arabic: نجس) means ritually unclean. According to Islam, there are two kinds of najis: the essential najis which cannot be cleaned and the unessential najis which become najis while in contact with another najis.Contact with najis things brings a Muslim into a state of ritual impurity (Arabic: نجاسة najāsa, in opposition to ṭahārah, ritual purity). Ritual purification is then required before religious duties such as regular prayers are performed.
Touching any Najis item including dogs or its urine etc does need Ghusl at all. You need to wash the part which touched the Najis item with water, then perform Wudhu and pray. It is a sinful act to delay performing the Prayer till it's time goes. Performing the Qadha namaz will not omit the sin of not praying within the time of the prayer.
You must perform your Namaz within its time under any circumstance.
Taharah is a real condition شرط واقعي in Prayers and fasting. Any worship which requires Purity (Taharah) is invalid if it was done with out purity.
If you could not learn basic rules of Ghusl and never been informed that Ghusl is obligatory in certain cases, which is very rare now a days, then the rule is different. But if you knew about Ghusl and it becomes obligatory in certain situations, and you did not know that it applies on you, and you fasted with out Ghusl, then you need to perform the obligatory Ghusl then perform every worship which was performed with out Ghusl.
You can read the verdict of Ayatullah Sustani as follows:
Ruling 1593. If a junub in the month of Ramadan forgets to perform ghusl and remembers after one day, he must keep a qaḍāʾ fast for that day; and if he remembers after a few days, he must keep a qaḍāʾ fast for all the days that he is certain to have been junub on. For example, if he does not know whether he was junub for three or four days, he must keep qaḍāʾ fasts for three days.
If you did not know, and you did not have the ability to educate yourself about these things, then your fasting is valid. Otherwise, you will need to do qadha.
ِAnd Allah knows best
Allah, The Glorious says in Quran (9:28) : إنّما المشركون نَجَس INNAMA ALMUSHRIKOON NAJAS. Verily the polytheists are impure. This a Quranic fact which all Muslims should follow.
Those who participate in Muharram believe and love Imam Husain (AS) being a divine leader of Truth, which means that they are not really polytheists even if their families are been classified as non Muslims. Their noble act in commemorating Imam Husain (AS)'s martyrdom reflects their undeclared faith in his values.
Allah Knows what is in the hearts and the acts usually reflect what is in the heart. That is why we take the acts who love Imam Hussain (AS) as an indication of their faith in him and his faith which is Tawheed.
Any Salah which was not performed with proper Ghusl must be made up again. If you are not sure how many prayers were invalid, you can estimate.
Just touching any impure part of the body during performing a Ghusl does not invalidate the Ghusl.
The Ghusl of Mayyit which is obligatory on every dead Muslim is enough for him.
When Ghusl is not possible, Tayammum must be performed to perform the obligatory Prayer within its time. Tayammum can be performed on any material of earth e.g. dry soil. Sand, stones, dust, etc. Wudhu does not suffice when Ghusl is not possible, but Tayammum is the only alternative.
If you are sure that your things were been touched by a Najis item with wetness, then you need to wash it to make it Taahir. But if you just doubt whether the item was really Najis or not, or whether it was wet or not, then such doubt has no value and your items remain Taahir.
There is an article entitled 'The Implications of Unbelief: Tracing the Emergence of Distinctly Shi'i Notions Regarding the Food and Impurity of Non-Muslims', by David Freidenreich, published in 'Islamic Law and Society', Vol. 18, published by Brill. This traces the development of Shi'i fiqh, and makes the point that the particular development of these rules developed in the 5th/11th century; i.e. the matter was much less clear prior to this era. It would require a study of the socio-political background to the development of this fiqh, in order to understand further what brought about this development. There are also a number of contradictory narrations in Shi'i sources regarding these rulings. Incidentally, Hindus also have rulings on purity with regard to non-Hindus.
It is allowed and not Haraam, but just Makrouh (disliked) to eat in the bathroom. If there is a condition forcing you to eat in the bathroom, you are allowed to do so.
No, sweat does not become najis in this case.
A general principle is when one is in the state of janabah, it is imperitave to hasten in doing their ghusl.
And Allah knows best.