Look at the number voting for Democrats as proof. ;-]
If only a remnant of each tribe went to Judah wouldn't they be diluted out? Did they marry outside of the individual tribes?
Intermarriage between tribes was very normal, but tribal affiliation only passed through the biological father.
Then there’s the story of Zelophehad’s daughters...
I am not certain what you are asking.
The father determines the tribe; the mother if a person is Jewish.
There are many Jewish people who have a gentile father, and are “tribeless” Jewish people. There are many gentiles that are part of a tribe, but are not Jewish.