Were there any Jewish scholars who, based on Jewish scholarship, acknowledged classical music (be it baroque to neo-classical) in a positive light and/or ever make mention of specific composers or pieces of music?
Salamone Rossi or Salomone Rossi (Hebrew: סלומונה רוסי or שלמה מן האדומים) (Salamon, Schlomo; de' Rossi) (ca. 1570 – 1630) was an Italian Jewish violinist and composer. He was a transitional figure between the late Italian Renaissance period and early Baroque.
I'm unaware of how many shuls, currently, sing works by Rossi, now, as many of his Cantorial works are choral, and, unfortunately, there aren't too many shuls with choirs in the U.S.
Your question doesn't clarify the type of "Jewish scholars" you are seeking. FWIW, The Belz School of Jewish Music, affiliated with Yeshiva University, includes a number of works by Rossi in its cantorial training. I think that considering that among the faculty are notable and knowledgable cantors such as Cantors Sherwood Goffin and Malovani, they would qualify as having both musical as well as Judaic scholarship in this area - enough to understand why Rossi was a significant composer.
As for what's considered "classical" music - since @DoubleAA mentioned "The Bach", would Shlomo Carl Bach ;-) qualify? As controversial as he was, he was also very much appreciated, as well, and proof is readily audible in shuls and weddings. (Without him, what would the trumpets play after the glass is broken?)