i like the name Aimee but im being bias as im Amy (the boring way, mum wanted it spelt aimee but dad said it was to hard and he wouldnt remember lol)

i to think it would be nice to have the first name end in an "a" it would sound nice with your other two girls. and also like the --a --a combo

but heres some suggestions anyway

Sienna Melissa
Isabella Melissa
Cassandra Melissa
Anya Melissa
Taylor Melissa
Ashleigh Melissa