I'm glad this article caught your eye and happy to discuss it!
While we tend to think of the Messianic Jewish movement as beginning in the late 1960's, there was actually a movement of Jewish Yeshua-believers in the late 1800's in eastern Europe which dwarfed our current movement--hundreds of thousands. Many of the leaders of this movement were trained, learned rabbis who came to believe the New Testament--men like Joseph Rabinowitz, Theophilus Lucky, Paul Philip Levertoff, R' Isaac Lichtenstein, R' Yechiel Tzvi Lichtenstein, and R' Daniel Zion. Some in our movement have actually described this time period as the golden age of Messianic Judaism.
What happened to all these? Sadly, the Holocaust all but wiped these communities out. However, there is a growing awareness and desire to connect to this heritage. Vine of David, the Messianic Jewish publishing arm of First Fruits of Zion, has led the way in bringing the works of these Messianic luminaries to light (no small task since many of these writings are in languages other than English!). They have a "Remant Repository" on their website where you can browse these valuable texts. They also have published Paul Philip Levertoff's Love in the Messianic Age and Franz Delitzsch's Hebrew translation of the gospels, beautifully designed and bound editions which befit their majestic contents.
R' Elijah Zvi Soloveitchik did not identify with this European Messianic community. However, he was one of several rabbis in modern Europe who looked into the New Testament and did not find it anti-Semitic or anti-Jewish but rather deeply resonant with the teachings of Jewish tradition...who saw Yeshua as a faithful Jew and who felt that the world would be a better place if everyone, Jews and Christians, came to understand this. In this sense, he was the forerunner of many contemporary Jewish and Christian scholars who (based on far more evidence than R' Soloveitchik had at the time) have come to the same conclusions. It is a marvel that, at a time when the idea of Jesus as a faithful Jew was much more rare, R' Soloveitchik and others (R' Jacob Emden comes to mind) somehow perceived this truth.
Boaz Michael (president of First Fruits of Zion) wrote a blog post commenting on this Tablet article about R' Soloveitchik. You can read it here: A Rabbi Who Loved Jesus: Preface to Mark.