Makrooh-e-Tahrimi

Q:

  1. Is it a sin to commit any act of makrooh tahreemee. How serious is it. Please give me reference from Arabic books like shami etc.
  2. After how long does a makrooh tahreemee become haraam?

Shaitaan

Q: My question is that who was shaytan before be was sent down from heaven? Was he a jinn? Or an angel? What is the difference between iblis and shaytan?