Various masaail of Salaah

Q: I have a question regarding the Hateem. Please assist.

The following riwayats come in Musnad-e-Ahmad, Abu Dawood and a few other famous Hadith books

روي عمرو بن حزم قال: رآني رسول الله صلى الله عليه وسلم متكئا على قبر. فقال: «لا تؤذ صاحب هذا القبر.» أو «لاتؤذه» رواه أحمد بإسناد صحيح. وعن أبي هريرة قال، قال رسول الله صلى الله عليه وسلم: «لأن يجلس أحدكم على جمرة فتحرق ثيابه فتخلص إلى جلده خير له من أن يجلس على قبر

From the above Ahaadith we understand that it is disrespectful to sit or stand on a grave. There are also many Tareekhi narrations that I have come across regarding the burial place of Hazrat Ismaaeel and Hazrat Haajar (alaimhimas salaam) that it is in the Hateem of the Ka'bah Shareef (albiet I am unsure of the strength of the narrations). There is also the narration of Hazrat Ummul Mumineen

عَنْ عَائِشَةَ أَنَّهَا قَالَتْ كُنْتُ أُحِبُّ أَنْ أَدْخُلَ الْبَيْتَ فَأُصَلِّيَ فِيهِ فَأَخَذَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِيَدِي فَأَدْخَلَنِي فِي الْحِجْرِ فَقَالَ : صَلِّي فِي الْحِجْرِ إِذَا أَرَدْتِ دُخُولَ الْبَيْتِ فَإِنَّمَا هُوَ قَطْعَةٌ مِنْ الْبَيْتِ فَإِنَّ قَوْمَكِ اقْتَصَرُوا حِينَ بَنَوْا الْكَعْبَةَ فَأَخْرَجُوهُ مِنْ الْبَيْتِ

How do we reconcile between these narrations and will performing salaah in the Hateem be tantamount to disrespecting the graves of Hazrat Ismaeel (alaihis salaam) and his respected Mother?

Q: When I am praying salah, can I turn to the left and spit thrice and say A'oozubillah because of whispering of Shaitan?

Can I do the same thing while making dua, whether my hands are raised or not?

I sometimes get whispers in my ears and I read A'oozubillah then spit thrice and continue making dua. It's not real spit, just the sound of spitting. Is it permissible?

Q: I massage over my penis with Roghan Beer Bahuti 2-3 times a week gently except the glans (front part). I have been advised to apply the above medicine. Can I perform namaz after applying this medicine?

Q: In sanna, instead of saying "Wata Baarakas mooka" I recited "Wata baarakas buka".

In Surah Ikhlaas instead of saying "QulhuwAllah" I recited "QulhuAllah".

In attahiyyaat I didn't pronounce the ha sound from throat.

Instead of pronouncing مُقِيمَ الصَّلَاةِ I pronounced "muqeemus salati".

In the tasbeeh of rukoo and sajdah I said "rabbial" instead of "rabbiyal" (I added yal instead of al) and I didn't pronounce the ha sound of these tasbeehaat from the throat.

I made all these mistakes without knowing it and I have made these mistakes in all my previous prayer since I started. Do I have to repeat all those prayers? 

Q: I accidentally put my prayer mat over a bone that my cat ate and I prayed over it. The bone was from halaal meat. Is this ok?

Q: I prayed zuhr and Asr salaah in a masjid which had a tomb in a seperate room besides the praying hall, but there was a window in the praying hall through which the tomb was visible. Will I have to repeat my prayer?

Q: Can I perform namaz after applying medicine on my penis? The oil is a medicine which was prescribed by the doctor.

Q: Is the ruling of 'weed' the same as khamar in the sense that if smoked, prayers are not accepted for 40 days? 

Q: How should a new Muslim perform salaah if he/she does not know any verses of the Holy Qur'aan?

Q: If someone doesn’t usually pray and just prays in front of people because if he doesn’t people will mock him, is it major shirk?