Very unlikely to be another traitor. Especially not one like Sicilian because... who cares about Sicilian? He's had even less of an impact in the series than Kanjuro did. If he was revealed as a traitor it wouldn't have any effect at all.
As for Carrot, she's a distinctly alright character. She provided a bit of levity in early WCI and has a fun enough relationship with Chopper. On the other hand, Oda completely dropped the ball on her relationship with Pedro by having them barely interact before his death, barely had a flashback showing their relationship after, and ultimately left me wondering why I should even care. Senor Pink's relationship with his dead family was more emotional in a single chapter than Carrot's supposed tragic backstory happening before our eyes over an entire arc.
Ultimately a minor character, overshadowed by others in every arc she's appeared, will vanish away after Wano (like she's done in Wano) to sail around the world and have an adventure without the Strawhats, where she doesn't belong.