The etc. here was removed from the 1920 LDS edition, perhaps because it awkwardly intervenes between thee (referring to Nephi) and the nominal whomsoever-clause that follows. The etc. seems to be referring to Nephi’s own seed, while the following nominal clause “whomsoever shall be called thy seed” refers to those who descend from others, not literally Nephi’s seed, that followed Nephi, as explained elsewhere in the text:
Similar explanations regarding the general terms Nephite and Lamanite are found in Jacob 1:13–14 and 4 Nephi 1:36–38. The original use of thee etc. in Alma 3:17 therefore seems to refer to Nephi and his seed (the Nephites proper) while “whomsoever shall be called thy seed” refers at least to the Jacobites and the Josephites and the Zoramites. The descendants of Sam were considered Nephi’s seed (as implied by 2 Nephi 4:11) and are therefore never separately listed in the text. In addition, the people of Zarahemla were eventually numbered as Nephites (as explained in Mosiah 25:13). And sometimes converted Lamanites were also counted as Nephites; for instance, the people of Ammon were “numbered among the people of Nephi” (the original reading in Alma 27:27). Apparently the etc. in Alma 3:17 refers to Nephi’s actual seed.
Summary: Restore the original use of etc. in Alma 3:17; it probably refers to Nephi’s literal descendants, as distinct from all the rest who would be called Nephites (the Jacobites, the Josephites, the Zoramites, etc.).