Even though I used to be a die-hard Yamato stan, I think Bonney would fit the best, both from perspective of character dynamic and from her strength (if anything, hanging around with Luffy's crew would fuel her creativity and cool usages of her DF, remember 2 Nikas?).
Yamato would be a great addition strength-wise, but I would prefer her to start her own journey, not as Oden wannabe (Wano has Momo now), but discovering who she is and what her dreams are now that Wano is free from Kaido. Unfortunately, she has 0 chemistry with the crew, and her Oden larping can be annoying.
Carrot had the best chemistry out of all the candidates imo, but she'd be absolutely lost in the background, since she's kinda weak for NW (remember Perospero "eat grass"?) and doesn't have a very distinguished trait. Also, her PU is very situational, needs some plot strings to get Sulong without the full moon. So imo Carrot would've been a fine addition sometime pre-TS to get better development. But yeah, at a certain point in WCI I was sure she's going to join, I understand barrel bros, the lead up was there.
Momo and Tama - no, they're kids. Even aged Momo is still as kid in an adult body and that would be creepy. You might want to argue that "but Bonney is also a kid", but she actually sailed the seas, alone and with a crew, and was notorious enough to get 100M bounty. Plus Bonney is what? About 12? While Momo and Tama are about 8? That's a big difference at that age.