It might not bother you, but I doubt anyone will pronounce Joan joe-ann.
Wow what a list!
Juliet Arline & Amelia Joan- classic, can't go wrong there, Adeline and Felicity are pretty, I'm just tired of the rampant popularity of Addy and Maddy names, I know two little Adeline's (I'm in the US, in the Boston area)
Poppy Arline and Thea Joan- This is my favorite, whimsical and fresh, I much prefer Thea to Lila
Boys: Felix Jackson and Jude David- perfect set!
Girl boy: Oliver David and Thea Joan- I like this, I love Thea and Jude together, I also love Thea and Felix
Does your grandma spell Jo-anne as Joan? Otherwise its probably going to be read wrong until you correct them.
My favorite pairings of yours:
GG: Vada & Tatum, Poppy & Thea
BB: Felix & Jude. (Otherwise I'd like Felix & Oliver! It just makes sense to me and sounds great together.)
GB: Vada & Jude, Oliver & Thea. (Otherwise I like Vada & Felix or Poppy & Felix. They both invoke happiness and playfulness!)
I read joan as jone. I love vada joan.
I like Amelia, Nolan and Elijah.
Not a big fan of felicity
Was "Vada" in My Girl supposed to refer to the Hindu sacred texts? I don't remember the movie very well.
Anyway, if it is, and you chose to use it, I thought you might want to know that the texts are the "Vedas" and the proper pronunciation is "Ved-a".
They're all fine names though I'm less fond of Poppy and Thea than the others.
Since you had asked for other combos I have to say my favored combo for two girls would be Adeline Joan & Juliet Arline.
For the boys I'd juggle the middles to match up Graham Jackson & Nolan David or Felix Jackson & Nolan David.
For boy/girl twins I love your first match up of Juliet Arline and Graham Jackson, that's my favorite pairing of all your choices.
My oldest daughters name is Vada and she LOVES it! That said she is totally the extroverted free bird of a child that could handle it. :)
Daughter #2's middle name is Juliet and then daughter #3 is Penelope but goes by Posey.
Apparently we have the exact same style because the 2 boy name we always came down to we're Jude and Graham!
Please don't be nervous about using Vada if it is a name you love. We do live in the south but we have received way more compliments than you would have imagined. That said, I'm totally okay with people not liking my names since I don't want them to become uber-popular!
Best of luck on your choices!