My mother's full name is
Andie, so that seems very normal to me. I think
Mia could definitely stand on its own. Both have great nn potential. For
Mia, I'd suggest
Miranda,
Maria,
Camilla,
Amelia,
Magnolia,
Milena,
Maia, and
Michaela. For
Andie, I like
Andrea,
Adeline,
Andromeda, Andalucia, or
Arden.