I really love Ava, despite its trendiness. I’d be tempted to use just May instead of Maeve because Ava and May sound like such a nicely matched sibset to me - but still out of all your options I like Maeve the best. I don’t think the similarities in sound matters personally as they still sound distinct enough not to be confused with each other which is the important thing.
But if it is a huge concern to you then of your list my 2nd choice would be Erin. Callie, Elsie, Elle etc are cute but they are nicknames - Ava is a complete name in its own right and it would be nice imo for her sister to have the same (and I personally find Isla super trendy and Mabel is still too elderly lady for me).