Ruling on applying the rules of tajweed to words other than the Quran

Is there any proven hadeeth to suggest that the Sahaabah danced, that is quoted as evidence for dancing in dhikr circles?

They usually recite al-Faatihah and the du‘aa’ (supplication) before starting to eat; what is the ruling on that?

There is nothing wrong with offering du‘aa’ together after a lecture

Ruling on one who misinterprets the attributes of Allah, may He be exalted