Will Everyone Be Treated Fairly?
Yes, absolutely. Allah always treats everyone with justice and fairness.
But read these verses of the Quran carefully, especially about the "People of the Book" (Jews & Christians):
These are the Verses of Allah: We recite them to you (O Muhammad peace be upon him) in truth, and Allah wills no injustice to the 'Alamin (mankind and Jinns).
And to Allah belongs all that is in the heavens and all that is in the earth. And all matters go back (for decision) to Allah.
You [true believers in Islamic Monotheism, and real followers of Prophet Muhammad, peace be upon him and commandments with him] are the best of peoples ever raised up for mankind; you enjoin Al-Ma'ruf (i.e. Islamic Monotheism and all that Islam has ordained) and forbid Al-Munkar (polytheism, disbelief and all that Islam has forbidden), and you believe in Allah. And had the people of the Book (Jews and Christians) believed, it would have been better for them; among them are some who have faith, but most of them are Al-Fasiqun (disobedient to Allah - and rebellious against Allah's Command).
[Noble Quran 3:108-110]
Whoever believes in Allah, as One God and is working righteousness as much as they can - and follows the most recent prophet sent by Allah, peace be upon them all, could well be a Muslim (submitter to the Will of Allah) and as such, it is up to Allah to be their Judge, just as He is the Judge in all matters.
Does Allah Treat Jews and Christians the same as Muslims ?
Some may question whether or no the "People of the Book" (Jews and Christians) living today might be considered as being "saved".
Actually, the Jews and Christians who believed in Allah as One God - and they tried to obey the commandments of Allah and follow the message which Allah sent with their particular messenger (such as Abraham, Moses, Jesus, etc.) are mentioned many times in Quran:
They are not all are the same; among the People of the Scripture is a community standing [in obedience], reciting the verses of Allah during periods of the night and prostrating [in prayer].
They believe in Allah and the Last Day, and they enjoin what is right and forbid what is wrong and hasten to good deeds.
And those are among the righteous.
And whatever good they do - never will it be removed from them. And Allah is Knowing of the righteous.
[Noble Quran 3:113-115]
Let's further consider what Allah tells us in the Quran about them:
Verily, those who disbelieved, and died while they were disbelievers, the (whole) earth full of gold will not be accepted from anyone of them even if they offered it as a ransom. [Noble Quran 3:91]
Those who die while disbelievers, will only receive payment of their good deeds here on earth, in this life.
But their deeds will not be accepted from them on Judgment Day, even if they spent the earth's fill of gold in what was perceived to be an act of obedience.
The Prophet was asked about 'Abdullah bin Jud'an, who used to be generous to guests, helpful to the indebted and who gave food (to the poor); will all that benefit him The Prophet said,
No, for not even one day during his life did he pronounce, 'O my Lord! Forgive my sins on the Day of Judgment'.
The Prophet Muhammad, peace be upon him, told us;
"If anyone of the People of the Book hears about me and the message with which I have been sent, and does not accept to surrender and submit to Almighty Allah in peace (Islam), then he will be in the Fire."
Allah tells us in the Quran, that He is the "Best of Judges" and certainly the final Judgment of us all rests with Him.