Interestingly enough this week's JUMP has a page showing off the anime designs of a couple of the army members (Opera, Mont d'Or, Amande, etc.), including that girl (whose name is something like Charlotte Mukle - I can't really think how that would be properly romanized ATM). It's interesting seeing a full character design for such a throwaway background character most people wouldn't even notice, though it makes sense why they would need one.
! Perhaps she will see some action if there's a final showdown at Cacao Island before the cake's completed.
! Cross-posting from the episode thread, but this week's JUMP had a page showing off the anime design artwork for several members of the Charlotte family and other members of the crew, including that Long-Arm girl who's shown up in a couple panels here and there, even giving her a name and confirming her a Charlotte. I bring this up because the staff said that Oda showed them his notebook containing all his sketches and information on the Whole Cake Island cast of characters beforehand, and this is probably the first instance visible to us the viewers of that paying off, since that's something that not even the manga or SBS has shown.
Now that a character like this gets a design sheet, I hope it doesn't go to waste.
In this instance, I personally forgive Oda for these underutilized designs because this man is racing time with his manga. It's literally impossible for Oda to give all these characters something to do without destroying the progression/pacing of the arc, WCI would have been a 5 years long arc or something, and even then, we still got dozens of characters that play an important part in this arc.
On the other hand, as the anime will most likely expand on the manga, I hope some of these unnamed characters to at least get couple more lines and maybe, just maybe, showcase their abilities (only when it's appropriate).
! For example, when Jinbe was blocking the attacks from three unnamed characters at the wedding, it would be neat if the give each one a unique attack. Or maybe give the fireball shooting guy a bit more variety, at least we know his specialty is fire. Last but not least, why not give Nusstorte, a character that was kept unnamed until his name dropped when he was defeated, some time to shine, maybe even show him marching to the Germa66 Kingdom.
It's a bit weird how this character we mentioned in the episode discussion immediately shows up in the magazine, what a coincidence!