Lehi “caused the sons and daughters of Lemuel to be brought before him.” This description suggests that either they were not present or that they were moved to a place of prominence from the group that was present. I lean to this latter explanation. It appears that all of Lehi’s sons were present during the pronouncement of the blessing upon Jacob because during that blessing Lehi addresses “my sons” (2 Ne. 2:14). The entire family was present, but those who were receiving the blessing moved to a location where they were directly in front of Lehi.
Lehi pronounces a collective blessing on all Lemuel’s children. It is identical to his blessing on Laman’s descendants. Doubtless, Lehi understood that their destinies were entwined, even if he did not foresee that they and others would be subsumed under the political name “Lamanites.”