Faraaidh of wudhu

Q: A scholar mentioned that it is fardh (obligatory) for two drops of water to fall from every hair and part of the skin that must be washed in wuḍūʾ. If this does not occur, it will be considered as masah (wiping) rather than proper washing. However, another scholar stated that as long as two drops of water fall from the entire limb, the wuḍūʾ will be valid, and it will be considered as washed. Which of these opinions is correct according to the Sharīʿah? 

Q: If a person is physically unable to lift his feet to wash them in the basin, is it permissible for him to perform masah (wiping) over the feet instead of washing? 

In such a case, if Ṣalāh is performed after doing masah instead of washing the feet, does the Ṣalāh need to be repeated?

Q: 

1. If wuḍuʾ is performed using a spray bottle, is the wuḍuʾ valid? 

2. With regard to the obligatory (farḍ) parts of the body that must be washed in wuḍuʾ, is it necessary for two drops of water to fall from each hair and part of the skin, or is it sufficient for two drops to fall from the entire organ (e.g., the face), even if only two drops fall in total after spraying water? 

Q: Is wudhu valid if someone wrote on their hands with pen and didn't scrub it off?

Q: Do you need to remove earrings when making wudhu?

Q: Is wudhu complete without washing feet?

Q: Before becoming a Muslim I made some tattoos on my body. Will my wudhu be valid with the tattoos and is it necessary for me to try to remove it? Removing tattoos can be very painful and laser treatment is very expensive.

Q: I use vaseline on my skin when it gets dry. Will my wudhu be valid if I perform wudhu without removing the vaseline?

Q: Does my hair turning greasy naturally after not washing it for like 3 days form a barrier so my masah for wudu isn’t valid?

Q: After salaah I saw a little dough stuck on my nail. Was my wudhu valid? Do I have to repeat my salaah?