I love Astrid for your sibset! I really do like your "A" theme, but I know what you mean by not limiting yourself. You don't want to name yourself into a corner
I also think Primrose would be lovely for a first name in your sibset. Alodie was a lovely suggestion!
Maybe: (note: this is a mix of boys and girls)
Athena, Aviana, and... Ellery
Athena, Aviana, and... Posey
Athena, Aviana, and... Amabel
Athena, Aviana, and... Prudence
Athena, Aviana, and... Rhyner
Athena, Aviana, and... Archer
Athena, Aviana, and... Adelaide
Athena, Aviana, and... Angelica
Athena, Aviana, and... Lyle
Athena, Aviana, and... Abeline
Athena, Aviana, and... Abbott
Athena, Aviana, and... Digby
Athena, Aviana, and... Abel
Athena, Aviana, and... Gwendolen
Athena, Aviana, and... Lorelei
Athena, Aviana, and... Israel
Athena, Aviana, and... Abram
Athena, Aviana, and... Seth
Athena, Aviana, and... April
Athena, Aviana, and... Piper
Athena, Aviana, and... Imogen
Athena, Aviana, and... Silas
Athena, Aviana, and... Emerson
Athena, Aviana, and... Thorsten