So I'm in the middle of separating Otomachi Una's different official outfits, and I've noticed she has especially lots of grey zones that are hard to determine whether warant the outfit tags or not, mainly because:
All three of her earliest voicebanks Sugar, Spicy and TalkEX have slightly different hair and hair ornaments. Meaning that she has no "default" hair, and they're frequently paired with alternate costumes. In this case one can argue that they serve just as a "default" hair and thus is not a direct reference to the outfit.
(Spicy has yellow streaked hair, and lighting-themed ornaments, Sugar has white bows with red stripes on the twintail ends, TalkEX has red hairpins hair ribbons and red glasses)
Spicy hair: post #3803699, post #5238312, post #3572800 (right) (also wearsing the Spicy hat)
post #2722544 has her body hidden, but the bows are exclusive to her Sugar bank
post #2722544 has the Sugar bow on one end of the twintails and the Spicy bow on the other end
And many arts depict her with the TalkEX hair because they're from artists who predominantly draw Voiceroid fanarts, (her Voiceroid bank inherited the TalkEX appearance)
post #3607390, post #4628906, post #4315831
Sidenote: post #5558466 is referencing the Spicy bank and post #5404165 looks like a combination of Spicy and Sugar, they at least deserve the adapted costume tag, but I'm not sue if we tag the referenced outfit or not.
Updated