You hit the point. Moravian Jewry was much reluctant to adopt both
surnames and given names by force of the decree issued in 1787.
Something must have happened around year 1828; since then the surnames
were used by Moravia Jews on regular basis.
ad H : Havakuk, Henoch and Hebron were only allowed.
ad L : Laser, Lazar, Levi and Lukas were only allowed.