Burial of the deceased

Q: 

  1. Should one sprinkle water on the qabr after burial? Many people do so. What is the shar'ee hukm?
  2. If plants grow on grave should they be cut?
  3. Should one put a twig on the qabr?
  4. People look at the mayats face and delay the burial. What should be done?
  5. Is there any Hadith regarding recitation of the first and last ruku of Surah baqarah after burial and also what is the hukm of dua in congregation after burial?