Respect for the Azaan

Q: I would like to know what is the Sunnah regarding when the Adhan is being performed. At our Ibadaat Khanna a few of our Muslim brothers in Islam, are talking or having a conversation one of them is busy scrolling on his cell phone. This happens on a daily basis and  they are over 45 and 60 years of age.

Salaah with Jamaat

Q: Does the narration of Hazrat Ali Radhiyallahu Anhu regarding the neighbour of the masjid "his salaah will not be proper unless performed in the masjid" also apply to the neighbour of a musalla (jama'at khana)? If he hears the azaan of the Musalla, will it also be waajib to attend that jama'at?

Going for Jamaat

Q: I am very much intersted in jamat and dawah work but recently i have heard scholars like Zakir Naik and few more saying that it is not in the seerah of Rasool of Allah (Sallallahu Alayhi Wasallam) nether in any hadith or Quran to go for jamat from city to city or counrty to counrty or for the weekly dawah (gusht) to the house of people to invite towards islam and nowhere is it written to go for 3 days or 40 days or 4 months in jamat. They also said that in the books like fazail-e-amal there are many zaeef (unauthentic) hadith so we must read only authentic hadith like sahih muslim and bukhari. Is it true? So I wanted to know is the work of jamat just a mere invention in islam or it is sunnah and recommended. Please give me hadith which supports your answer.