Will a person come out of the fold of Islam by committing sin?

Q:

  1. I just want to be clear about this, if you do haraam things like receive interest from a bank, drink alcohol etc but consider them haraam, so if you consider haraam things to be haraam but still you do them, would you come out of the fold of Islam?
  2. A Hadith said with people little amount of Imaan will come out from hell but as far as I know Quran doesn't says people will come out from hell. Qur'an says those who enter hell will remain in it forever. So will those people be in hell forever and is above hadith correct?

Correction of duas for eating

Q: 

  1. Please clarify if the dua for eating has wa ala barakatillah or if it is just wa barakatillah without ala, which one is Sunnah and rewarding?
  2. The dua after eating is it wajaalana minal muslimeen or wajaalana muslimeen, which one is Sunnah and rewarding?

​Please write the duas in Arabic with Harakat and reference from Hadith.

Wazifa for psoriasis

Q: My dad is suffering from a skin disease called psoriasis and it has been for quite a long time now. My great grandfather and my grandfather had the same disease. Please give me some duas for this disease? Can I ask him to recite the dua of Ayub Alaihi Salam as well? 

Placing a line of bricks around the grave

Q:

  1. Laying a layer of brick stones around a grave for identifying the presence of a grave but not building anything over the grave, is it permitted or not? Does it come under the category of a pukka grave which is prohibited in Shari'ah? We see in Jannatul Baqi that many graves have a demarcation with a layer of rock stones around them.
  2. What is the meaning of the statement that 70000 dead will be taken out from a single grave on the Day of Resurrection? The numbers 7, 70, 700, 70000 are used in Hadiths and in the Quran to describe different situations. Can we take these numbers in the literal sense or do they convey any other meaning?