I really like Ellis and it's my favourite from your girl list. I like 'gan/gen' ending names for girls very much, but not so much Brogan - would you consider Regan, Keegan, (suggested at the risk of being hung drawn and quartered by MN who hate people using these names for girls) Tegan? Also other Br names such as Bronte, Brenna, Brynn or Briar? Hallie/Allie are very bland to me and the worst on the list. Lux is rather cool for a girl but don't like it for a boy.
I love Finn and like Alistair. Arlo and Aiden seem bland, dull and in Arlo's case too trendy. Aiden is over-used. Finn is popular but feels cool to me, and Alistair has the strength of tradition behind it.