Here Oliver Cowdery omitted the verb phrase shall be when he initially took down Joseph Smith’s dictation in 𝓞. Oliver later supplied the verb phrase, perhaps after he read the text back to Joseph (the supralinear shall be is written with somewhat heavier ink flow). The 1874 RLDS edition accidentally replaced the auxiliary shall with will, apparently prompted by the preceding “wilt thou”. This error was corrected in the 1908 RLDS edition, probably by reference to 𝓟. In theory, either auxiliary is possible in this passage. For some discussion regarding the variation between shall and will in the Book of Mormon text, see under 2 Nephi 27:15.
Summary: Maintain the verb shall in Alma 31:29, the reading of the earliest textual sources.