One wonders here if we shouldn’t expect strewn rather than strewed as the past participle for the verb strew. According to the Oxford English Dictionary, both are possible past participial forms; thus the critical text will accept strewed, the reading here of all the extant textual sources (𝓞 is not extant for this word). In modern English, strewn is the overwhelmingly favored form, but strewed also occurs. For instance, in Mark Davies’ Corpus of Contemporary American English, there are 1352 instances of the past participle strewn but only 6 of the past participle strewed. As far as scriptural usage is concerned, there is only one instance of the verb strew in the Book of Mormon, namely, here in Ether 14:22; there are none at all in the King James Bible.
Summary: Maintain the past participle strewed in Ether 14:22, the more difficult reading for modern English readers (who prefer strewn).