so Carrot appeared on the ideal moment.
From all the characters people have been suggesting as the newest Strawhat, Carrot by far has currently the highest chance of actually joining:
1) She's female
Considering the current ratio is 8 males for 2 females, female characters have a higher chance than male characters to keep things more balanced.
2) She's a mink
Luffy has a love for the weird and the unusal. A cyborg, a human reindeer, a skeleton...so a female rabbit surely would be a perfect match for the crew.
3) Personality quirks
Almost all Strawhats also have weird personalities or some weird quirks. A chronic lier, several perverts, a gold digger...now this is rather common for many characters, not just the Strawhats, but still Carrot has showed to be rather odd.
4) Strength
All the Strawhats had to train for two years, which makes it rather difficult for anyone to join as that person needs to have a certain amount of strength, however it would be rather illogical that all the Strawhats had to train for 2 years, but that someone else can join just like that and keep up. So there has to be something that balances out that 2 years of training. Now Minks are born warriors, they have a natural aptitude for fighting and Pedro implied in this chapter that Carrot's strength seems to even be for a mink rather high.
5) Adventurous
IMO this might even be the most important characteristic of Carrot. It was quite strongly emphasized this chapter that she has never left Zou and is severely naive in regards to the outside world and as a result she's highly excited to the prospect of traveling around. This is a quality many other characters that people have suggested lack and it's a quality many people also seem to ignore. For example characters like Rebecca or Viola had no reason to leave and this also applies to Vivi. She is the sole heir of a mighty country and her father is in bad health, so she really can't just leave to go on an adventure.
