Kufr

Taking an Oath for acts of kufr

Q: A person who promised or said or took a qasam etc. to commit an act of kufr or commit an act of kufr at the time of death or join shaytaan or follow him or become brothers with him or accept his offers or accept it at the time of death or die as a non-muslim or commit a sin etc. Does it suffice to seek Allah's forgivness alone?

Is it kufr to say that a certain medicine cures

Q: Is it kufr to say that this medicine cures like acne as example. Like is it kufr to put your trust in that medicine? Before I read a fatwa of someone asking that question but they said its not, I don't really remember. But now I am hearing that Allah cures him not the medicine, so I am confused. So whenever I say this medicine has a cure for this, I think is the cure from Allah or Allah put the cure in the medicine. But I know if Allah wills he wouldn't let him be cured by that medicine. Did I commit kufr?

Utterances of kufr

Q: If a muslim attributes to himself an other religion by saying, for example, "I am a Jews" or "I am a Christian" or "the christian are better than muslim in aqida". Does such a person become a kafir even if he uttered the statement jokingly and even if he did not know that it is kufr to say such a thing?

Cursing Allah Ta'ala (Naudhubillah)

Q: I should not be saying this but it is bothering me. When something bad happens to me I lose my temper and say very very bad things about Allah Ta'ala like he is not merciful, he is cruel, and I also curse Allah (Naudhubillah). Do I become a Kafir on saying this? Are all my good deeds wasted by saying this? If I don't become a kafir, can I repent for these sayings?

Uttering a word of kufr without understanding it's meaning

Q: If a word/sentence does constitute Kufr and a person says that but he does not understand its meaning, or does not intend its meaning, or out of ignorance, or by mistake does that make him a Kafir? Similarly, if doing something constitutes Kufr and a person does that out of ignorance, or by mistake does this make him a Kafir? I read this on the web: "...if an ignorant individual states a word and does not know that this word is Kufr, according to some scholars he will not be Kafir because he will be excused for not knowing. Some scholars had said they will be Kafir..." 

And this:

" ...some scholars do not even excuse the mistaken individual who does not know the word he uttered or action he did indicates Kufr and makes Takfir. Especially the Mawarau'n-Nahr (Samarqand and Bukhara) Ulama from the Hanafi Madhhab have held the topic very tight and do not accept ignorance to be an excuse almost in every matter..."

And this:

" Aliyyu'l-Qari states: “if the statements of a Muslim indicates Kufr from 99 angles and Islam from 1 angle he will not be made Takfir of based on %1” and continues to explain the matter of stating Kufr as a mistake. In another place he mentions things similar to the Qadihan Fatawa regarding the same matter. In that narration he states: “The individual who states Kufr without knowing (it is Kufr) will not be Kafir. However, if this matter is a matter of Din that necessarily must be known, then he will not be excused for ignorance, and will be made Takfir of." 

What is the majority view from all the madhabs in this issue, and which view should be acted upon?