Hasidim

Question

Could the rav please explain to me some things about hasidim? 1 - What is their justification for davening mincha after it is already dark outside? Is a mitnaged allowed to do this when he is davening in their shuls? 2 - Hasidim seem to light candles and to cancel tachanun every second or third day. Is it permissble for a mitnaged to do this, or should he refrain from lighting the candles and say tachanun even when he is davening with hasidim who are not? 3 - If you follow the gra and say no yotzrot on yom tov and the special shabatot, what should you do if you find yourself in a hasidic shul when yotzrot are being said? Should you walk out? Sit quietly? Stand quietly? Say the yotzrot? Or go elsewhere? 4 - If you hear a hasid laining, and he says "Yankof" instead of "yaakov" or "hee" instead of "hu" and so on, is this, for you, a kosher laining? What about for the reading for Zachor and Esther?