After wiping the nape during the wudu, people also interlace the fingers, wipe the back of the hand, over the knuckles, towards the arms. Is this OK? Can a woman use a razor to remove her hair? Why, in your view, are the Shias not Muslim? The Shia at least say La ilaha illAllah, Muhammadur Rasulullah, isn't it? Aren't they our brothers and sisters? Can we just let people alone because Allah (SWT) will decide what to do with everyone, including the non-Muslims? How do we people in regions where the sun sets around midnight determine prayer timings for Maghrib etc?

Wiping the neck in wudoo' is based on a weak narration. The authentic narrations which describe the wudoo' of the Prophet (peace be upon him) do not mention wiping of the neck. Interlacing the fingers and doing a wiping motion is called takhleel of the fingers. This is based on authentic hadiths so it is permissible.

A woman is not allowed to shave her head and be bald-headed unless if that is done for a reason like sickness. There is a hadeeth in Tirmithi, which prohibits that. In addition a woman who shaves her hair with a razor blade will be imitating men and this is also not permitted. 

As  for the question on  the Shias that is  an aqeedah issue which Inshallah can be tackled at length in that subject.  However, I would like to point out that the kalima  Laa ilaha illa Allah has rights. So if a person says the kalima and does not respect its rights then his statement is hollow and his actions will not be accepted.  If a person says the kalimah and does not back it up with an action, which contravenes the principles of Islam, then his statement is just mere talk with no action behind it. The scholars of Islam never mentioned a general takfeer (declaring someone a disbeliever) of the Shia. They applied takfeer to the leaders and scholars of the Shias who openly call to their mathhab despite knowing the truth. As for the ignorant masses these are Muslims unless if they stick to their mathab after knowing the truth.

 As for the fact that the sun sets after midnight the scholars have said that the people of that land should follow the timetable of the nearest Muslim country.