1. There were different schools of thoughts as far as Fiqh (Ahkam) is concerned. At one point of time, it happened to be announced as four Sunni Fiqh namely Hanafi, Shafei, Maliki and Hambali. In Shias we do have Ja'fari and Zaydi Fiqh. There is another fiqh which still does exist named as Ibadi mostly in Oman. All these groups have a different of approach in deriving Islamic laws from its original sources.
2. No, one can't recite all the Nawhas unless he/she has checked or knows that on the basis of probability, the thing which is written is okay to recite. Some of the lyrics just go against the Ja'fari 'Aqaid and few others are not facts as far as historical reports are concerned. To minimize the destruction, one needs to check it with an expert in the filed.
Mostly the Akhbariyyat what is seen in Indo-Pak region is not an academic Akhabrism, rather it is based on emotional feelings and exaggerated understanding of the narration.
3. One has to preach the true message of Islam and bring about the reform as per 11:88 (verse 88 of Surat Hud)
He (Prophet Shoayb) said, "O my people, have you considered: if I am upon clear evidence from my Lord and He has provided me with a good provision from Him... ? And I do not intend to differ from you in that which I have forbidden you; I only intend reform as much as I am able. And my success is not but through Allah . Upon him I have relied, and to Him I return.