What are some of the literary devices used in the poem "After Fifty Years" by William Faulkner (besides similes, imagery, and metaphors)? Also, what is the main message of the poem in relation to time, change, and old age?

In the poem, William Faulkner uses the sonnet form of two stanzas, the first with eight lines and the second with six lines. He also uses regular rhyme schemes: ABBA, BCCB, DEDEED. The poem uses a conceit, an extended metaphor throughout the entire poem, which is comparing the woman’s life to a house. Although specific elements could be taken literally, such as the empty house and her looking in the mirror, overall the imagery serves to support the author’s metaphorical usage.
The poet also employs a type of metonymy, synecdoche: the substitution of the part for the whole, in comparing two associated things. Two places he does this are in calling her suitors the men’s “arms” and in referring to her potentially successful matches with elite men as “crowns.” Personification also can be found, as the woman’s mirrors are said to “know.”
The small amounts of alliteration, repetition of an initial consonant sound, that are used in several places gain additional power by their repetition further down, although not necessarily in alliterative relationships the second or third time. Similarly, the poet uses the same word or different forms of it, or similar words in different contexts: the device of polyptopton is here used to emphasize their importance. A limited amount of assonance, repetition of a vowel sound, is also used, often in conjunction with alliteration.
Examples of alliteration include, in line 1, the initial letter H four times. Line 4, “blind bent,” is followed by “birds” in line 6 and “bind” in line 7 and then echoed or slightly changed in lines 12–13: “Bound,” “bent,” “blind,” and then finally, in line 14, “body.” Assonance appears in line 4, short E; in lines 11 and 12, OU is actually rhymed: “crown” and “bound.”
The overall impression the speaker gives is of a longstanding love and its loss. The man is still bound by love to the woman, but her life is loveless as an empty house. The poem seems to be concerned with what might have been more than what actually happened.
https://www.poetryfoundation.org/poems/53984/after-fifty-years