Is it a condition that a woman should untie her locks while making Ghusl (ritual bath)?
Ghusl from Janabah (ritual impurity), or menstruation obligates that water reaches the roots of the hair in order for the Ghusl to be valid, but if it doesn`t, then hair locks must be untied for water to reach them, and for Ghusl to become valid.
What should I do in order to wake up for Fajr (dawn) prayer?
All perfect praise be to Allah, The Lord of The Worlds What should I do in order to wake up for Fajr (dawn) prayer? Answer: Some of the acts that aid in offering Fajr prayer are: 1- Going to bed early. 2- Willingness to wake up. 3- Reciting Al-Korsi verse from Chapter Al-Baqarah. 4- Taking refuge in Allah from the cursed devil, and making ablution immediatley after being awake, but it is preferable to ask someone to help in this regard to perform the Fajr prayer. And Allah Knows Best.
What is the ruling on congratulating others on the arrival of Ramadan?
Congratulating others on the arrival of Ramadan is permissible.
If someone does it to express their love for worship and the blessings of Ramadan, and congratulates their fellow Muslim, they have done something good.
The Prophet ﷺ said: "Shall I not tell you something that, if you do it, you will love one another? Spread peace (Salam) among yourselves." [Narrated by Muslim]
Giving Salam is a prayer for peace and safety.
Is the one who gives up on marriage because he can`t afford it considered sinful?
Marriage is desirable, but one who can`t afford it isn`t considered sinful. However, he should supplicate to Allah, and seek His forgiveness.