Missing units from my wish list except GR units are below.
Eden and Memento are absolutely required for later missions, and cannot play any more without implementing the alternative units.
(If you have some black units, no problem. And no chance for me)
Chloe,Noel,Franc,Nagi and Liana are highly required. (Liana is in 'premium summon', but...)

I'm using Eliza,Cloris,Calliope,Nenya as Magical Rear in JP version, but no problem until now. (Planing to get Ryuryu additionally)
I planned to get Kagura in EN version, too. But I'm thinking I can wait until Eliza...

I hope Nagi. She is great as 'Duelists'!