1- Unrestricted Takbir (mutlaq) is not limited to a specific time, and it is Sunnah to say it all the time, morning and evening, before prayer and after prayer, at all times. Restricted Takbir (muqayyad) is limited to the time immediately after prayer. 2- It is Sunnah to recite unrestricted takbir during the first ten days of Dhul-Hijjah and all the days of Tashriq, starting from the beginning of the month of Dhul-Hijjah (i.e., from sunset on the last day of Dhul-Qi’dah) until the end of the days of Al-Tashriq, which is when the sun sets on the thirteenth day of Dhul-Hijjah). 3-With regard to restricted takbir, it starts from Fajr on the day of ‘Arafah and lasts until the sun sets on the last day of the days of Tashriq. 4-The scholars have different views on the formulas of Takbir which are explained in the detailed answer.

Takbir in unison before ‘Eid prayer is an innovation because there is no evidence for it, and the Prophet (peace and blessings of Allah be upon him) said: “Whoever does an action that is not part of this matter of ours will have it rejected.” What `Umar (may Allah be pleased with him) did is not evidence for reciting takbir in unison; rather what `Umar (may Allah be pleased with him) did was to say takbir by himself, and when the people heard him they said takbir, each one by himself. This does not indicate that they all said takbir in unison.

There is no authentic hadith from the Prophet (peace and blessings be upon him) which would indicate that the one who recites the last 10 verses of Surah Al ‘Imran will have recorded for him the reward of spending the night in worship.

Among the adhkar that can be recited after prayer are the following: 1. Astaghfirullah 3 times 2. Allahumma anta al-salam wa minka al-salam tabarakta ya dhal-jalali wa’l-ikram 3. Reciting Ayat al-Kursiy silently, 4. Reciting Qul Huwa Allahu Ahad, Qul a'udhu bi Rabbi’l-Falaq and Qul a’udhu bi Rabbi’l-Nas.

A person should not remember Allah on his tongue (by speaking) when he is in the bathroom, rather he should do so in his heart.