The alliteration is that she's telling you how her life was and how some days it was good and other days it wan't so good. She uses alliteration because she wants her reader to know how days were during her life. Although she wasn't a slave she still had a hard life and the alliteration she uses represents that and how she wishes things were easier and she's saying that life was hard for folks back then. I hope this helps.
I would Say none of these are colloquialisms, I looked up what colloquialisms are, unless these words specifically are in sayings, none of them are <span>colloquialisms</span>
