Treaties are with political entities and not religions as a whole. Among the Christians: While there was a treaty with the tribes of Najran there was a simultaneous war with the Byzantines and the status of Negus's Ethopia was probably one of friendship.
With that said, the things mentioned in the treaty are pretty much standard parts of the contract of Dhimmis (non-muslim subjects of an Islamic state) in shariah. They pay Jizyah and are not forced to convert, nor are their places of worship destroyed. A variation is Kharaj, where a conquered people are allowed to govern themselves and pay a tribute, based on the actions of the Prophet with the Jews of Khaybar. Dar ul Aman (Domain of peace) is a separate concept, where there is an equitable treaty without tribute. For details see Hidayah.
No Christian would ever be forced by the Muslims to become a convert
to Islam.
The above is applicable because of the commandments of the Quran and not just the treaty. The People of the Book, Jews and Christians, are not forced to convert if their land is conquered through War, nor are they to be forced to convert when they are being ruled as citizens of an Islamic State ... instead they pay Jizyah and are allowed to practice their religion.
Quran 9:29 Fight those who do not believe in Allah or in the Last
Day and who do not consider unlawful what Allah and His Messenger have
made unlawful and who do not adopt the religion of truth from those
who were given the Scripture - [fight] until they give the jizyah
willingly while they are humbled.
And:
Quran 2:256 There shall be no compulsion in [acceptance of] the
religion. The right course has become clear from the wrong. So whoever
disbelieves in Taghut and believes in Allah has grasped the most
trustworthy handhold with no break in it. And Allah is Hearing and
Knowing.
From Tafsir Al Qurtubi:
ليست بمنسوخة وإنما نزلت في أهل الكتاب خاصةً، وأنهم لا يُكرهون على
الإسلام إذا أدّوا الجزية، والذين يُكرهون أهلُ الأوثان فلا يقبل منهم
إلا الإسلام فهم الذين نزل فيهم { يٰأَيُّهَا ٱلنَّبِيُّ جَاهِدِ
ٱلْكُفَّارَ وَٱلْمُنَافِقِينَ } [التوبة: 73]. هذا قول الشعبيّ وقتادة
والحسن والضحاك. والحجة لهذا القول ما رواه زيد بن أسلم عن أبيه قال:
سمعت عمر بن الخطاب يقول لعجوز نصرانية: أسلمِي أيتها العجوز تسلمي، إن
الله بعث محمداً بالحق. قالت: أنا عجوز كبيرة والموت إليّ قريب! فقال
عمر: اللهم ٱشهد، وتلا { لاَ إكْرَاهَ في الدِّينِ }.
[second] This verse is not abrogated. This is was specifically
revealed about the People of the Book that they will not be forced to
accept Islam when they pay Jizyah. The ones who will be forced are
idolators, from them nothing will be accepted except Islam, and about
them the verse 9:73 was revealed
This is the saying of Shabi, Qatadah, Hassan and Zahak and the
evidence for this is the tradition that Zaid bin Aslam narrated from
his father. He said: I heard Umar bin Khatab, he was asking an old
Christian woman to accept Islam: "Accept Islam and you will be saved,
verily Allah has sent Muhammad with the truth". She replied: "I am
very old and close to death." On this Umar said: "O Allah! Bear
witness." and then he recited: "Let there be no compulsion in
religion".
