There was much linking between black and Haides, the lord of the dark world, as it hinted death, so was it even more ominous a color for clothes than in our age? Did common people not care about it or were the "virtuous" people who cared not for such superstitions?
Is there some clue to the dating of Alcman? He speaks, among other things, of the Tyndaridai, so maybe he was of a late Archaic date? Or perhaps an earlier date? It seems to me that he should be before Tyrtaios, and that Tyrtaios should be at the time of Theopompos which was the time of the gradual conquest of Messenia, and before the time of Anaxandridas when the gradual alliance with the Peloponnese was done. But I just don't know, so please someone can reach out a thoughtful reflection?
I am reading Pomeroy - Spartan Women which talks quite a bit about Alcman and his Partheneion I, the longest extant lyric poem from the early Greek archaic period. Because the main section of the text that survived was performed by young maidens and it is about young maidens talking about themselves, it it quite relevant as a primary source for the study of women in archaic Sparta. On the topic of the dating of the poem and on the time that Alcman may have lived in Sparta, Pomeroy says that
Alcman lived in Sparta in the archaic period, probably after the Second Messenian War, but before the ensuing militaristic reforms had profoundly transformed society. Textual evidence points to the late seventh century. Archaeological evidence indicates that he died no later than 570.
I would recommend not merging two different questions into a single post, I find it confusing and it makes it harder to answer. If you have further questions similar to the one on the dating of Alcman, you may want to post them on the biweekly featured post that is specifically for short, specific questions.