Here the 1830 edition changed the modal verb will to would. The occurrence of will does seem somewhat jarring with respect to the preceding occurrences of should and would and, in particular, the following would, all of which are conditional modals. In this passage Mosiah is speaking hypothetically about how Aaron might change his mind and the difficulties that might result from such a change of mind. The use of the will implies more certainty than would; yet we expect the same level of certainty since the two modal verbs refer to causing “wars and contentions” and “the shedding of much blood”, both of which are related.
One obvious possibility is that the original text read would for both which-initial relative clauses, which would mean that the first instance of would was accidentally changed to will. Yet there is no nearby use of will that could be responsible for such a change. Moreover, there are no examples in the manuscripts where will and would were ever mixed up. The scribe here in 𝓟 is Hyrum Smith, who is not a particularly good scribe. But we have so little of his hand in 𝓟 that we cannot say much about his error tendencies, at least with respect to modal verbs.
Ultimately, the issue comes down to how egregious the use of will is in this passage. Given the paucity of manuscript evidence for mixing up will and would, the safest solution would be to restore the earliest reading, the somewhat difficult will. In other words, the critical text will follow the reading in 𝓟: “which will cause wars and contentions among you”.
Summary: Restore the modal verb will in Mosiah 29:7, the reading of the printer’s manuscript; although the will here is somewhat difficult (given the surrounding conditional modals would and should ), the critical text will follow the earliest reading since the less subjective nature of will is not excessively difficult to interpret.