No OTL American music, but the American influence will follow audio technology from the twenties into the sixties. Alternative inputs will change music in general. You can't compare AH entirely to OTL. What sounds "terrible" to us is the norm of ATL. Don't forget the conservative reaction to American rock-and-roll in the late fifties.Very interesting question. American music would be much the poorer. No gospel, no ragtime, no jazz, no R & B, no rock & roll, no rap, no hip hop. This is making me very sad. That leaves us with country western, which does have Black influences, European style classic music, and ballads. Latin music would come in during the 20th Century. Without 'Black music American global cultural dominance would be much weaker. Gospel has great spiritual power, and helped make America one of the most devotional countries in the world.
The Acadian migration was more complicated than many think. Some 11,000 French Acadians were expelled from 1755-1764. Most dispersed along North American coasts, some all the way back to Europe. The Spanish recruited them as settlers in Louisiana because they felt French Catholics would be more supportive than possible English settlers after the Seven Years War. Only some 4,000 survived the migration but those who did had large families. There were already many French in Louisiana, as well as Spanish. In 1809, another group of French migrants came From Haiti to Cuba to New Orleans:Cajuns are French descendants from Canada?
Maybe more Celtic influence as well.