Do they fit the prophecy checklist?:

Have they been scattered?

Deuteronomy 4:27 - "And the Lord will scatter you among the peoples, and you will be left few in number among the nations where the Lord will drive you."       

Deuteronomy 28:64 - “And the Lord will scatter you among all peoples, from one end of the earth to the other, and there you shall serve other gods of wood and stone, which neither you nor your fathers have known."   

Nehemiah 1:8 - "Remember the word that you commanded your servant Moses, saying, ‘If you are unfaithful, I will scatter you among the peoples,"       

Psalm 44:11 - "You have made us like sheep for slaughter and have scattered us among the nations."       

Jeremiah 9:16 - "I will scatter them among the nations whom neither they nor their fathers have known, and I will send the sword after them, until I have consumed them.” 

Ezekiel 12:15 - "And they shall know that I am the Lord, when I disperse them among the nations and scatter them among the countries."     

Ezekiel 20:23 - "Moreover, I swore to them in the wilderness that I would scatter them among the nations and disperse them through the countries,"

Ezekiel 22:15 - "I will scatter you among the nations and disperse you through the countries, and I will consume your uncleanness out of you."

Zechariah 7:14 - “and I scattered them with a whirlwind among all the nations that they had not known. Thus the land they left was desolate, so that no one went to and fro, and the pleasant land was made desolate.”

Luke 21:24 - "They will fall by the edge of the sword and be led captive among all nations, and Jerusalem will be trampled underfoot by the Gentiles, until the times of the Gentiles are fulfilled."

When they return from captivity they'll dwell safely in their land. Not eventually but immediately.

Psalm 14:7 - "Oh that the salvation of Israel were come out of Zion! when the LORD bringeth back the captivity of his people, Jacob shall rejoice, and Israel shall be glad.

Jeremiah 23:6 - "In his days Judah shall be saved, and Israel shall dwell safely: and this is his name whereby he shall be called, The Lord Our Righteousness."

Jeremiah 32:37 - "Behold, I will gather them out of all countries, whither I have driven them in mine anger, and in my fury, and in great wrath; and I will bring them again unto this place, and I will cause them to dwell safely"

Ezekiel 36:24-25 - "For I will take you from among the heathen, and gather you out of all countries, and will bring you into your own land. Then will I sprinkle clean water upon you, and  ye shall be clean : from all your filthiness, and from all your idols, will I cleanse you. "

Ezekiel 34:28 - "And they shall no more be a prey to the heathen, neither shall the beast of the land devour them; but they shall dwell safely, and none shall make them afraid."

Ezekiel 34:11-13 KJV :

[11] For thus saith the Lord GOD; Behold, I, even I, will both search my sheep, and seek them out. [12] As a shepherd seeketh out his flock in the day that he is among his sheep that are scattered; so will I seek out my sheep, and will deliver them out of all places where they have been scattered in the cloudy and dark day. [13] And I will bring them out from the people, and gather them from the countries, and will bring them to their own land, and feed them upon the mountains of Israel by the rivers, and in all the inhabited places of the country.

Isaiah 2:4 - "And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more."

It says the nations will learn His ways & there will be peace in the nations

Micah 4:2-4 - "And many nations shall come, and say, Come, and let us go up to the mountain of the Lord, and to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for the law shall go forth of Zion, and the word of the Lord from Jerusalem. 3 And he shall judge among many people, and rebuke strong nations afar off; and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up a sword against nation, neither shall they learn war any more. 4 But they shall sit every man under his vine and under his fig tree; and none shall make them afraid: for the mouth of the Lord of hosts hath spoken it."

Why would the true Israel people choose to associate themselves with the line of Japheth knowing how important the chosen lineage from Shem is?

Genesis 10:2-5 - "The sons of Japheth; Gomer, and Magog, and Madai, and Javan, and Tubal, and Meshech, and Tiras. And the sons of Gomer; Ashkenaz, and Riphath, and Togarmah. And the sons of Javan; Elishah, and Tarshish, Kittim, and Dodanim. By these were the isles of the Gentiles divided in their lands; every one after his tongue, after their families, in their nations. "

Scripture says there will be a fake Israel masquerading as the real one and a different people in their land

Revelation 2:9 - "I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan."

Rev 3:9 - "Behold, I will make them of the synagogue of Satan, which say they are Jews, and are not, but do lie; behold, I will make them to come and worship before thy feet, and to know that I have loved thee."

Zechariah 9:6  "And a bastard shall dwell in Ashdod, and I will cut off the pride of the Philistines."

Genesis 9:27 - "God shall enlarge Japheth, and he shall dwell in the tents of Shem; and Canaan shall be his servant. "

Job 9:24  The earth is given into the hand of the wicked: he covereth the faces of the judges thereof; if not, where, and who is he?

Remember scripture says the whole world has been deceived

Revelation 12:9 - "And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him."

Jeremiah 16:19-21 KJV:

[19] O LORD, my strength, and my fortress, and my refuge in the day of affliction, the Gentiles shall come unto thee from the ends of the earth, and shall say, Surely our fathers have inherited lies, vanity, and things wherein there is no profit. [20] Shall a man make gods unto himself, and they are no gods? [21] Therefore, behold, I will this once cause them to know, I will cause them to know mine hand and my might; and they shall know that my name is The LORD.

Matthew 25:41-46 - "Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: For I was an hungred, and ye gave me no meat: I was thirsty, and ye gave me no drink: I was a stranger, and ye took me not in: naked, and ye clothed me not: sick, and in prison, and ye visited me not. Then shall they also answer him, saying, Lord, when saw we thee an hungred, or athirst, or a stranger, or naked, or sick, or in prison, and did not minister unto thee? Then shall he answer them, saying, Verily I say unto you, Inasmuch as ye did it not to one of the least of these, ye did it not to me. And these shall go away into everlasting punishment: but the righteous into life eternal."

Matthew 12:46-50:

46While he yet talked to the people, behold, his mother and his brethren stood without, desiring to speak with him. 47Then one said unto him, Behold, thy mother and thy brethren stand without, desiring to speak with thee. 48But he answered and said unto him that told him, Who is my mother? and who are my brethren? 49And he stretched forth his hand toward his disciples, and said, Behold my mother and my brethren! 50For whosoever shall do the will of my Father which is in heaven, the same is my brother, and sister, and mother.

The Bible never says only some tribes would return to the land and the rest  would be lost tribes.

The covenant starts and ends with Israel and welcomes those grafted in.