Five Daily Prayers

• Are my previous prayers invalid because I used to say in prostration "Subhana Rabbi al-A'la" (Glory be to my Lord, the Most High) with a fatha over the yaa in "Rabbi" instead of a kasra, even though I know now that it should have a kasra, given that I had doubts about how to pronounce it previously but did not ask?
• What should I do about the recurring thought of interrupting prayer while performing it, and am I obligated to repeat it for the third time, knowing that I am someone who is often afflicted with doubt concerning purity, Al-Fatihah, prostrations, and rak'ahs?
• What is the ruling on praying over a deceased person while they are inside a covered coffin?
• What is the authenticity of the hadiths mentioned in "Kanz al-Ummal" regarding the virtues of the five daily prayers and the divine covenant for those who maintain them, and is it permissible to act upon them?
• How can one get rid of the continuous daily practice of masturbation that has been ongoing since the age of fourteen, and which has led to loneliness, excessive overthinking, and difficulty in consistently performing prayers?
• What is the ruling on looking at a wristwatch during the Witr prayer to ascertain the time remaining until the Fajr Adhan?
• Is someone who tries to be diligent in performing the five daily prayers and makes up for those he missed due to work considered a disbeliever, and is it permissible to marry him?
• What is the ruling on sleeping on a mattress that has slight impurity (such as dry drops of urine), and does that affect the validity of the prayer performed in the clothes one slept in, and is it obligatory to make up past prayers due to ignorance of the transmission of impurity through sweating?
• Is it permissible to recite the Istikhara supplication immediately after an obligatory prayer, and is it necessary to repeat the prayer if the person performing Istikhara remembers the intention for Istikhara at the end of the Fajr prayer?
• How sound are the hadiths: "A man's voluntary prayer performed where people do not see him is equivalent to twenty-five of his prayers performed in plain sight of people," and "The virtue of a man's prayer in his house over his prayer performed where people see him is like the virtue of obligatory prayer over supererogatory prayer"? Are they supported by other hadiths, and are they specific to the pre- and post-BPM Sunnah prayers or to all supererogatory prayers?
• How can Ja‘far ibn Abī Ṭālib’s statement to the Negus, “He commanded us to pray and to give zakat and to fast,” be reconciled with the time of the revelation of the command concerning prayer, zakat, and fasting, taking into consideration that the first emigration occurred in the fifth year of the Prophethood?
• Do the doubts and delusions about the presence of someone seeing and hearing me, and the belief of hearing praise and admiration for my voice while reciting the Quran or praying, count as showing off (riya') or self-admiration, even though it is a recurring whisper (waswasah) despite seeking refuge from it?
• Is it permissible to pray with the palms partially or fully covered by the sleeves of a long undershirt?
• Is the sister's daughter unlawful for the questioner's son to marry, given that the questioner breastfed her a few unsaturated times – she doesn't recall the exact number, whether four or five – on the fifth day of her birth, where the milk was scant and did not satiate the child, and all of this occurred within five hours?
• What is the ruling on one who omits washing the hands after waking up from sleep, concerning the validity of his ritual purity for prayer, taking into account the view of those who deem it obligatory? And is it sufficient to wash them before performing ablution?
• Does performing prayers without ablution last Ramadan affect the validity of the fast, and what should be done now to make up for those prayers after repentance?
• What is the ruling on the prayer of one who precedes the Imam in the prayer area?
• How did the opinion of the imams differ from the opinion of the Companions — may God be pleased with them — regarding the excommunication (takfir) of one who abandons prayer out of laziness, and were they unaware of that?
• What is the ruling regarding prayers performed while doubting the presence of urine droplets, before noticing and taking precautions against them, and must they be made up if their number cannot be determined?
• What is the way to remain steadfast in prayer and abandon masturbation despite the overwhelming lust?
• Are these secretions considered "madhy" (pre-seminal fluid), and should one follow the Maliki school of thought, performing ablution and praying more than one obligatory prayer with the same ablution, or what should one do?
• What is the ruling on someone who pronounces the letters of the first Taslimah incorrectly by mistake, and does the Imam bear that on his behalf?
• Is it permissible for a girl to stipulate as her mahr (dowry) that her fiancé commit to performing the five daily prayers, instead of requesting gold, given that he is lax in prayer due to work, and her aim in this is to encourage him to adhere to them?
• Are the prayers that were performed in clothes acquired from ill-gotten gains valid and acceptable?