Conditions & Fundamentals of Hajj and Umrah

Q: I know that if a person will be performing qurbaani, then he should avoid removing his hair and nails during the first ten days of Zul Hijjah, until his qurbaani animal has been slaughtered. 

However, I was told that when performing hajj, you should remove your hair and nails before the 7th of Zul Hijjah. My questions are as follows:

1. If you are performing both qurbaani and hajj, then when should you remove your hair and nails – should you remove them before the 7th of Zul Hijjah or before the 10 days of Zul Hijjah?

2. Do you need to perform the qurbaani yourself, or can it be performed on your behalf at home by some family member (i.e. parents, siblings or children)?

Q: When one is making tawaaf, is one allowed to:

1. Drink zamzam that someone is giving out?

2. Drink zamzam by proceeding to the nearest tank, without being in dire need of the water, but to quench one's thirst?

3. Sit and rest for a while, drinking zamzam, etc.?

Q: I would like to know that when a female makes tawaaf and men bump into her or touch her, is it better for her not to make tawaaf and only make when the crowd is small so she can be sure no men touch her? Or is it ok to continue making tawaaf? If the woman is elderly is it ok?

Q: After completing my first umrah, I removed all my hair using a zero trimmer. After 2-3 days, I performed a second umrah and again removed my hair using the same zero trimmer (though the hair was very little). I was in doubt in regard to whether I did the correct thing or not by using a zero trimmer. Is my second umrah valid as I used a zero trimmer? 

Q:

1. Can I wear sunglasses when making tawaaf for umrah and hajj? 

2. Can I wear perfume at the time of tawaaf for umrah and hajj?

Q: I would like to know what kind of slipper I can wear in the state of ihraam. Is it a must to wear a 2 belt slipper or I can wear the slipper which is open in the front and back?

Q: Can someone who doesn't have a knowledge of the holy Qur'aan perform Hajj?

Q: Can a patient who has a urine problem perform umrah by wearing a pamper (diaper) in tawaaf?

Q: I work as a flight attendant for an airline. Sometimes when I come to Jeddah, once I come to the hotel, I shower and put on my ihram on and go and do umrah. Is this ok?

Q: Is it permissable to make tawaaf for family members who are not present in Umrah.