Sajdah and Jalsah

Q: My question is regarding the dua said in sujud and ruku.

In ruku if one says Subhan a Rabbiyal Azeem 5 or 7 times and then Subhanak Allahumma Rabbana wa Bihamdika Allahumma ighfirli and in sujud Subhan a Rabbiyal A'laa 5 or 7 times, then Subhanak Allahumma Rabbana wa Bihamdika Allahumma ighfirli and then Astaghfurillah al-Adheemal-ladhi la illaha illa Huwal-Hayyul-Qayyum wa atubu ilay a few number of times (unspecific number) and the proofs for the following being:

A person who says:

“Astaghfirullah al-’Azeem al-lazi la ilaha illa Huwal-Hayyul-Qayyum wa atubu ilaih ” [I seek the forgiveness of Allah the Mighty, Whom there is none worthy of worship except Him, The Living, The Eternal, and I repent unto Him] … even if he has committed sins as much as the the foam of an ocean, still he will be forgiven. [Abu Dawud- 2:85/ Tirmidhi 5:569]

and Interpreted Translation Narrated `Aisha: The Prophet (ﷺ) used to say frequently in his bowing and prostrations "Subhanaka l-lahumma Rabbana wa bihamdika, Allahumma ghfir li" (Exalted [from unbecoming attributes] Are you O Allah

And for a longer sujud adding the following duas: Allahumma a Inni Ala zikrika wa shukrika wa husni ibadatika and the asking Allahumma Ajirni Min A Naar 3 times and Allahumma adkhilni Jannatul Firdous 3 times.

Proof for the following being: “The nearest a slave can be to his Lord (Allāh) is while they are prostrating, so increase in supplication” (Ṣaḥīḥ Muslim, Musnad Aḥmad) .

It was narrated that Anas (may Allah be pleased with him) said: The Prophet (peace and blessings of Allah be upon him) said: “Whoever asks Allah for Paradise three times, Paradise will say, ‘O Allah, admit him to Paradise.’ Whoever seeks protection from the Fire three times, Hell will say, ‘O Allah, protect him from the Fire.’” Narrated by al-Tirmidhi, 2572; Ibn Majah, 4340

Note: This is just a pattern of supplication which the person has memorized as it is easy for him to remember these in respective sujud and ruku. The person does not consider this to be as an action of Rasulullah (Sallallahu Alaihi Wassalam) but just some duas from the Sunnah that he can easily remember and supplicate from. Is this Bidah or is this allowed?

Q:

1. Can I read dua's from the Quraan, like starting with "Rabbana" while in sajdah during fardh salaah?

2. Can I make dua in my mother tongue while in sajdah during fardh salaah?

3. Can I do both of these during nafl and sunnah salaah?

Q: I read somewhere that you cannot lift your foot in prayer and it invalidates the prayer. But when I stand up from the sitting or prostration posture, I need to adjust my feet so that I am again facing qibla directly (my body seems to be a bit lost of the previous position). I heard it invalidates prayer. Hence if I am very slightly not facing qibla, I would just not lift my feet to adjust it. What should I do? 

Q: My question is regarding namaz. I am offering Esha prayer and in the sajdahs of the first rakat i say "Subhan a rabi ul alaw" three times and in the sajdahs of the 2nd raka I say "Subhan a rabiul a alaw" 5 times. Is saying "Subhan a rabiul alaw" three or five times that make impact??