Shorter version. The statement "(Almost) all of Emily D's poems can be sung to the tune of X" strongly implies that (almost) all of her poetry is written in the same meter, that the poems are metrically uniform. In fact, there is no such uniformity. There are at least three or four basic stanza patterns (3333, 4444, 3343, 4343) plus many variations on these four patterns in 1775 poems! And that's only counting the basic accentual pattern, not all the other rhythmic irregularities in individual lines and stanzas, or the fact that not all her poems are even written in quatrains.