One wonders here if the singular bloodshed might be an error for the plural bloodsheds. Elsewhere in the original text, when bloodshed(s) is conjoined with other nouns, we always get agreement in number with some immediately conjoined noun (in the following list, each case involving textual variation in number is marked with an asterisk):
bloodshed conjoined with a singular noun
bloodsheds conjoined with a plural noun
(For discussion of the instances showing variation in number, see under each individual passage.) Mosiah 29:36 is the only place in the original text where the singular bloodshed is combined with plural nouns: “all the wars and contentions and bloodshed”. As noted under 2 Nephi 10:6, there has been a noticeable tendency in the history of the text to replace the plural bloodsheds with the singular form, so perhaps the same error occurred in Mosiah 29:36 early on in the transmission of the text. Even so, the use of the singular bloodshed will work, so perhaps what we have here is a unique reading in the text. The critical text will accept the earliest reading here in Mosiah 29:36 since it is possible, even though it differs from all other conjoined occurrences of bloodshed(s).
Summary: Maintain in Mosiah 29:36 the singular bloodshed since it will work, even though everywhere else there is number agreement between bloodshed(s) and an immediately conjoined noun.