At the time prior to the Assyrian Exile, did the Tribes of Israel not intermarry? And / or live in other Tribes' lands for other reasons? I mean, besides Levi and Shim'on? For example, were Judah's descendants allowed to live in Israel? Were there Issakhar's descendants in Judea? We know that the 10 Tribes were taken into Assyria, but does it refer to the tribes? Or to the population of the land of the 10 Tribes?

Would it be correct to look at the dominant traits of character of the person and based on those match them to the characteristics Jacob gave his sons in his final blessings?

It was established in the 1970s that Ethiopian Jews were the descendants of Dan. I am not challenging that, (and it's wonderful that we have found one of the Lost Tribes), but how? And why aren't other Tribes found yet?

The Sages said that a Ger (convert) is really an Israelite from one of the Ten Tribes. Is there a way to tell which one?

When we were returning from Galut Bavel in Nechemia the issue came up some could not verify status as Cohanim, they kept suffic status till Cohain Gadol could verify with Hashem using Urim and Tumim/Choshen Mishpat.
There should also be genetic markers to be determined.

So when the real return of the 10 Tribes begins, the Urim and Tummim will be found? Or will Hashem provide new Urim and Tummim? Or do we have Cohanim who know where they are?