Faraaidh and Sunnats of ghusal

Q: 

1. A person begins fasting in the state of janaabat. Regarding ghusl in this state, is the ghusl valid if the water does not reach the inside of the throat or the inside of the nose (i.e. these actions cannot be exaggerated out of fear of the fast breaking)? Will the ghusl be valid if the water did not reach deep into these areas? Or would the person make ghusl washing the nose and mouth as in wudhu and upon breaking the fast would the person then gargle the throat and wash the inside of the nose properly?
2. A person forgets that they are fasting, and thus gargles and washes the nose intensely so that water is accidentally swallowed. Is the fast broken, bearing in mind that the person forgot that s/he was fasting?

Q: Is it necessary to remove surma and kaajal from the eyes when taking a ghusl?

Q: During ghusal I doubted that some shell of popcorn is left between my teeth and gum. I tried hard to remove it with help of brush but could not succeed so I left it by considering it as my doubt and I performed all my prayers but in the night pieces came out. Now what should I do?

Q: Is permissable for a lady to not wash her hair for ghusal-e-janabah at fajr time and just make masah if it is very cold or if she gets headaches when washing her hair or if she is sick?

Q: If a person has a tattoo which is into his skin,will his ghusl be valid?

Q: My problem is that when I perform Wudhu and Ghusl, the water does flow over my skin but my skin does not get wet. I think the reason for this is that my skin is too dry. I think my Wudhu/Ghusl will not get accepted if skin does not get wet so I apply soap then my skin does get wet for a very short period. However, that is causing me problems, the soap finishes too quickly, Wudhu and Ghusl take too long and lots of water is wasted. Please tell me if I pour water over skin but skin does not get wet will wudhu/ghusl be accepted?

Q: In case a person completes his/her bath and realizes that a part might have been left dry, what is the state of the ghusal?

Q: If one is making ghusal then must all the plaque from ones teeth be removed.