Scribe 2 of 𝓟 copied the text from 𝓞 into 𝓟 as “leaving no one to reign in his stead”. Oliver Cowdery, presumably when he proofed 𝓟 against 𝓞, corrected no one to none. This change here does not appear to be due to editing since in all other passages that refer to an inability to find someone to rule, no one is the pronominal form, not none:
In none of these passages did Oliver emend no one to none, which argues that the change here in Alma 1:1 was simply because scribe 2 of 𝓟 mistakenly wrote no one and Oliver corrected it to none, the reading in 𝓞. This means that there is variation in the text between no one and none in this context, with three occurrences of no one and one of none.
Elsewhere the manuscripts have numerous examples of both no one and none, of which the vast majority are invariant in the textual history. There are three other cases for which there is textual variation between no one and none:
Joseph Smith was responsible for the change in Alma 6:5. The two other instances, in Mormon 8:14–15, are more difficult to analyze since for that part of the text both 𝓟 and the 1830 edition are firsthand copies of 𝓞. See under Alma 6:5 and Mormon 8:14–15 for discussion. Also see the general discussion under negation in volume 3.
Summary: Accept in Alma 1:1 Oliver Cowdery’s correction in 𝓟 of no one to none; since no one is preferred elsewhere when referring to finding someone to rule, the unique use of none in Alma 1:1 probably represents the reading of the original manuscript, no longer extant here.