Just to jump in here. During the
Assyrian invasion there were people from each tribe who ran to the South into Judea for protection. So yes, there were Asherites, Gadites, Ephriamites etc. but the bulk of the people were carried off and assimilated into the Gentile world. They lost their identity just as Yahweh said they would in the book of Hosea. That was part of their punishment. It was Yahshua’s primary purpose to come to this world to REGATHER the house of Israel and restore the Kingdom of Israel. What was the apostles last question to Yahshua before He ascended? When are you going to RESTORE
the Kingdom of Israel? and what did Yahshua answer?
(Acts 1:7 KJV) And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
These are the times of Restoration. We are being given back our identity. We are being shown the paganism that infiltrated our Faith. We are going back to the Scriptures of the entire Bible to rediscover the Truths that the Father wants us to walk in. Today the call of Eliyah is going out make STRAIGHT your paths, the Messiah of ISRAEL returns. I fear the holy Scriptures far more than any doctrine of man.
Not disagreeing with any of your points, but many from the Northern Kingdom migrated to the Southern Kingdom well before the Assyrian invasion. Not from fear of conquest but because of the apostasy started in the Northern - the worshiping of idols in the “High Places” begun after the split by Jeroboam (I Kings 12).