To answer your last question first, logic dictates that when someone comes who fulfills all the requirements of the Mashiach, then we will know that he is of the line of Zerubavel.
Rambam Hilchos Melachim (Chapter 11)
Halacha 1 starts
- In future time, the King Moshiach  will arise and renew the Davidic dynasty, restoring it to its initial sovereignty. He will
rebuild the [Beis Ha]Mikdash and gather in the dispersed remnant of
Israel. Then, in his days, all the statutes will be reinstituted as in
former times. We will offer sacrifices and observe the Sabbatical and
Jubilee years according to all their particulars set forth in the
Also, if Eliyahu hanavi comes first, he will testify as to who he is. However, this should not be needed since the Rambam includes "renewing the Davidic dynasty" as part of his accomplishments. This can only be done if he is a member of that dynasty.
As to your first question, I discuss it at which kings must Moshiach descend from?
There is a web site that discusses the lines of descent from Zerubavel
through the ages.
Descendants of Zerubavel Rashei Galut (Exilarchs), Gaonim and Rabbis.
The page is too big to copy here, so just follow the link.
Descendants of Zerubavel, great-grandson of the last king of the
There are many versions of these lines of descent. The principal ones
are shown here:
1)Ibn Yachya (Don Yechia), Charlap – “The Book of Destiny – Toledot
Charlap” – 1996 Arthur F. Menton.
Drawn from fifteen family trees researched by the author.
See explanations under “What the Experts Say, Articles”.
2) Ibn Yachya (Don Yechia), Charlap – “Sefer Kidushei” Avraham Moshe
3) “Makor Niftakh LeBeit David” – 1969, Moshe Yair Weinstok.
4) Dayan – “Yashir Moshe”, 1864, Moshe Dayan.
5) Abarbanel – undated handwritten manuscript from the collection of
the late Rabbi Shmuel Gorr, held by Chaim Freedman.
Reference was made to “Elef Margaliot” 1993, Meir Wunder.
Several websites have differing versions, such as
Ongoing research may be reflected in future alterations to the chart.
** Traditional descent of the Maharal of Prague from Yehudah Liwai Hazaken is challenged by several researchers and requires further
(Englard – “Tzfunot” 12, quoted by Rosenstein, “Avotaynu Volume XII,
Number 1, Spring 1996, reprinted in Englard’s “ Letoldot Kheker
Hayukhsin Beyisrael” 2004). )