Regarding The Beatles: Americans tend to consider Meet The Beatles their debut album, but it actually isn’t. In March of 1963 EMI released their true debut, Please Please Me, in England, but Capitol (EMI’s U. S. equivalent) passed on the album. Vee Jay Records obtained the rights to the album, changed the title to Introducing The Beatles, and released it in January of ’64, the same month Capitol released Meet The Beatles. By then Capitol had seen the light (or smelled the money ;-) .
Meet The Beatles is unquestionably, in historical terms, THE "debut" album of my lifetime (said as a U.S.A. resident). It sounds like what we consider the early Beatles sound: Merseybeat. Please Please Me/Introducing The Beatles doesn’t. It contains covers of a lot of U.S. Girl Group, R & B, and Show Tunes (a favorite of Paul McCartney), and not particularly well done, imo.