Briony definitely works with Austin, Neil and Griffin. Of the girl choices, I really like Brenna, however, I'm not usually into matching twin names. Still, I like it best and it sounds nice with Briony (how are they pronouncing this?).
At least they begin with the same consonant blend. Can you imagine repeatedly calling Briony and Blake, for example? I know me and I'd turn them into Bliony and Brake. LOL.
that's true! lol we we're trying to say Briony and Brenna together and you can say them both but we always stumble over them or stutter lol and they keep changing their minds it drives me crazy!