In this passage we have two minor changes in the text. In the 1840 edition, whosoever was replaced by whomsoever. From a prescriptive point of view, whosoever is correct here since it acts as the subject of the whosoever-clause. For two other instances where the 1840 edition switched whomsoever and whosoever (but not always consistently from a prescriptive point of view), see under Alma 3:10 and Alma 3:17. Here in Alma 47:27, the 1874 RLDS edition restored the original (and grammatically correct) whosoever to the RLDS textual tradition. But that same edition replaced the following word, the past-tense loved, with the present-tense loveth. This error in tense was corrected in the 1908 RLDS edition, probably by reference to 𝓟.
Summary: Maintain the original reading in Alma 47:27, the wh-form whosoever and the past-tense loved: “whosoever loved the king / let him go forth and pursue his servants”.