Interfaith Dialogue - Spritual Jurisdiction of the Prophets

Verily, Allah, azza wa jall, has said in the Qur'an (what
means): "Say (O Muhammad SAAW): O mankind! Verily, I am
sent to you all as the Messenger of Allah - to Whom belongs
the dominion of the Heavens and the Earth. La illaha illa
Huwa (none has the right to be worshipped but He). It is
He Who gives life and causes death. So believe in Allah
and His Messenger (SAAW), the Prophet who can neither read
nor write, who believes in Allah and His Words, and follow
him so that you may be guided." [Al-A'raf: 158].

The prophet (SAAW) said (what means): "And the Prophets
were formerly sent to their people only, whereas I have
been sent to all mankind." [Al-Bukhari and Muslim].

If so, Islam says that "All mankind is under the Spiritual Jurisdiction
of Prophet Muhammad's (PBUH) ministry" in some sense. Of course,
Almighty God is always the final authority, but in some sense.

They are to follow the religion that was given to him, he will intercede
for all of creation on the day of judgment which indicates his position with allah in relation to the rest of creation.
He will be the first to interced for everyone then the prophets will in interced for there own nations.

Tirmidhi (gharib): Ibn `Abbas narrates: "Some people close to the Prophet came and waited for him. When he came out he approached them and heard them saying: What a wonder it is that Allah Almighty and Glorious took one of His creation as His intimate Friend -- Ibrahim -- while another one said: What is more wonderful than His speech to Musa, to whom He spoke directly! Yet another one said: And `Isa is Allah's word and His spirit, while another one said: Adam was chosen by Allah. The Prophet said: I heard your words, and everything you said is indeed true, and I myself am the Beloved of Allah (habibullah) and I say this without pride, and I carry the flag of glory on the Day of Judgment and am the first intercessor and the first whose intercession is accepted, and the first to stir the circles of Paradise so that Allah will open it for me and I shall enter it together with the poor among my Community, and I say this without pride. I am the most honored of the First and the Last and I say this without pride."

What does Islam say about Issa (PBUH)? "He was a Prophet to the Jews"? Does that mean that all non-Jews are exempt from his teachings?

Here you are taking the word jews to mean a race of people while it is also a religion, so if you were to follow judaism the religion you do not have to be of the 12 tribes of judah. So in that respect any christian who follows the teaching of jesus (sallah llahu alaihi wa sallam) is of the Ummah/ nation of Jesus.

You have to remember that back then many people were on the religion of there forefathers regardless of what it was but some were guided to the truth and adopted that religion. Allah judges you by what is in your heart or what you believe regardless of your tribe. There were many christian tribes in the prophet muhammads (sallah llahu alaihi wa sallam) time which were arab egyption or other races and he considered them to be christian or people of the Book as allah refers to them in the Quran.

But Almighty God saw fit only to send a "global Prophet" in Prophet Muhammad (PBUH) only c. 610 CE. Therefore, all mankind has been called, directly, only since that time? Anything the non-Jewish world picked up prior to 610 CE is extra, and bonus points, but in some sense "superfluous"?

Each nation prior to islam was sent a messenger to guide it to the truth, so each nation had there guidance from Allah. After Allah sent messengers and prophets to each of the nations of the World He finaly sent his last messenger and made him a Prophet to All mankind ie there last chance at guidance after they had rejected the messengers that had been sent to them.

The non jewish world could have learnt from jesus if they chose and they would have been considered his followers but his mission was to the jewish people, he said i was sent but to the lost tribes of israil (or something similar) that was his mission there is nothing in that prohibiting his followers after his time spreading the truth but his job was to guide the jewish people back to light it was there last chance with Allah as he has sent them neumorous other messengers beffore him which they persecuted and killed.

Up untill his time Allah considered them his chosen people on earth he was trying to guide them back.

You read the manuscript. How is it relevant to you? If I could similarly replicate the pure originals of all 24 Hebrew Prophets (Isaiah, Daniel, Ezekiel, etc), how relevant would they be to you?

Our prophet came with esentialy the same message as the other abrahamic faiths but if you look at there teachings from his time to our prophet, Allah made some things prohibited while others he made permisable, eg alchohol and pork. So the other scriptures would be accepted as revelation but we could not follow them in matters of law or sipritual guadance as the Quran abrogates prior revelation while confirming other parts of it.

You have to also understand that each prior revelation was specific for a group of people, for there benefit primarily while the Quran is for all of mankind, the miracle of our prophet was the Quran and it is a shifa/healing and guidance for all of mankind.

Bluntly put, does Islam say that (non-Jewish) Christians are applying to themselves a message that Almighty God only intended for the Jews?

as i said above a revelation sent to a specific people is for the ultimate benefit of those people as allah is considereing there nature/charachter/habits/spirituality, this doesnt stop others from following it and i am not saying Allah will not accept the religion of non jewish christians at that the time of revelation but it was not intended for All mankind.