The editors for the 1920 LDS edition deleted the second ever in the apparently redundant “which ever were ever since the fall of Adam”, giving “which ever were since the fall of Adam”. (The text has read were instead of the original was ever since the 1837 edition.) Another possible emendation would have been to delete the first ever, giving “which were ever since the fall of Adam”. The last relative clause in this sentence supports maintaining the ever before the be verb (“or which ever shall be”). Of course, the redundancy is only mild here in Mosiah 4:7 and can actually be accepted in the original text if we treat the phrase “ever since the fall of Adam” as parenthetical: “which ever was (ever since the fall of Adam) or which is or which ever shall be”.
Another possibility is that the second ever was actually the word even (“which ever was even since the fall of Adam”), which would then parallel (in part) the final part of this passage (“which ever shall be even unto the end of the world”). Confusion between even and ever is possible since Oliver Cowdery’s n’s and r ’s are often identical in form (see, for instance, the discussion under Mosiah 2:15–16 where two manuscript examples of mixing up even and ever are listed).
Nevertheless, the text normally has ever since rather than even since—and always in passages referring to the beginning of the world (each marked below with an asterisk):
Note that in Mosiah 13:33 Oliver Cowdery initially wrote even since in 𝓟 but later corrected this to ever since (the level of ink flow is slightly heaver). In the current text, there is, in fact, only one occurrence of even since:
It is quite possible that this single remaining example of even since is an error for ever since. For discussion, see under Helaman 8:19.
The critical text will accept the repeated ever here in Mosiah 4:7 since the mild redundancy is not egregious. Note that the RLDS text has maintained both occurrences of ever in the relative clause “which ever were ever since the fall of Adam”.
Summary: Restore in Mosiah 4:7 the repeated occurrence of the adverb ever (“which ever was ever since the fall of Adam”); the original redundancy is not all that difficult.