Types of Treatment

Q: I'm not sure if you are aware of the recent epidemic of christian healers that's infecting our community like the plague. Christians seem to use the possibility of their mislead leaders healing people, claiming to be annointed by god(though they haven't a clue about who or what god is), as a defence to our statements about the authenticity of Islam and the quran. My question is what should our answer be when they challenge us boasting the capability of their leaders? How is it possible that their leaders do such things? What does the Quran say about this?

Q: Is the practice of "Acupressure" permissible in Islam? Some information regarding it, http://www.eclecticenergies.com/acupressure/howto.php

Q: Medically, a doctor can stop life-support treatment in the following cases: brain dead, no-hope situation or if the treatment will cause more harm than benefit. Is this permissible to stop treatment on a patient in the above circumstances?

Q: 

1. Is it permissible to practice yoga for the sake of fitness? 
2. Is reiki (an art of healing) permissible? 
3. Is Tai-chi (a form of Chinese self defense and healing) permissible? 

Q: For the purpose of curing the sickness near the private parts, can we massage recited olive oil or zam zam water on the private parts as a medicine. I have heard that in Mecca people bath with zam zam water, that even reaches the private parts. 

Q: Is it permissible to use a copper bangle due to medical reasons (men & woman)?