Shaking hands and hugging one's mother's friend

Q: My mother has a friendship with a woman (just a normal friendship). So, sometimes, when I meet her, my mother expects me to shake hands, hug and kiss her, or at least one of the mentioned. I have actually been doing this for last several years. I also need to mention that she is not a mahram to me. In addition, she does not observe hijab in front of non-mahram males. Alhamdulillaah, since last year, I actively started learning my religion. I will be 20 years old next month (September), by miladi calendar. I need to mention that the friend of my mother is more than 35 years. Most likely, she is between 35 and 40. I heard or read somewhere that shaking hands with old women is permissible if there is no fear of fitnah. I can verify that I have no fear of desire or anything attracting when I meet her since she is and looks quite old and has a husband. Also, the same with hugging and kissing if I am not wrong. However, these are things I heard or probably read from an untrustworthy source. 

Ghusal on the 10th day after haidh

Q: If a girl got her periods on Saturday morning 11 am- 12pm and on the tenth day which is Tuesday morning her periods end.

1. Can she perform ghusl after fajr or is it necessary to perform ghusl sharp at 11 am?

2. Can the ghusl be performed at any time after fajr or whats the shariah rule regarding it? If the girl wants to fast on Tuesday, can she bath after fajr and keep the nafl fast?

Chairs in the Musjid

Q: In our Masjid, as in many others there is a proliferation of chairs that are being used by Musallees to perform their salaat.

1. Can one Musallee (who uses a chair) place another chair reserving that place for another Musallee (who also uses the chair) in the absence of that Musallee. This implies that should the second Musallee arrive for Salaat (if and when?), he then has a place that has been reserved for him. This process is used to reserve a dedicated place/point in the Saff for themselves for all of their Salaat regardless if one of them attends or not.

2. For all intents and purpose is their merit in the suggestion that persons who use chairs to perform their salaat should perhaps be seated in the end/wing of each Saff?

3. Would it be appropriate to request that chairs be returned to their “designated” area after each Salaat and not left in the Saff once the Salaat has been completed.