[gmw]

This sort of thing is one reason why it's worth maintaining lists of characters, places and so on: such lists allow you to more easily see unintentional patterns.

That said, my first reaction to the OP was: "'a' names!"? Previous advice I had read warned against using names starting with the same letter: Edwina, Edith, Evelyn, Eloise, etc. Which I would describe as 'e' names. Hence my initial confusion with the OP.

I can see a word-shape similarity, combined with 'a' being the common vowel (but they are not using the same sound, nor even all the same number of syllables). If there are five characters and these are the names then I can see your problem - because, at the very least, it seems statistically unlikely. But if these were five names picked from 20 in the story then I might have less of an issue.

I must presume that the context is such that these five names are important enough (used enough) that the (slight) visual similarity is causing some difficulty. Also, I am presuming there is not some deliberate intention on the part of the author(s) to make these names seem similar. Such as a line from the movie George of the Jungle: "Thank you, Gunner, Gunter, Hans, Jan... and Phil.", where the one name that stands out highlights the similarity in the others to some effect.


Edited to add: I'm not really doubting what you say is true in context, that the criticism if valid, only that without the context the advice of the OP is incomplete.