These are all from the pretty cure franchise but unfortunately I don't know them all. Can someone with more knowledge help me out filling out the characters?
It will be at least collectively longer than Sailor Moon, should Fresh get a second season.
As for watching it, you could get away with just watching one series and leaving out the rest.
Mishou Mai/Cure Egret
from "Splash Star"Hyuuga Saki/Cure Bloom
from "Splash Star"Asahina Mahiru/Cure Sundy
from "Bouken! Precure days"
(fanmade,unofficial)Yamabuki Inori/Cure Pine
from "Fresh!"Higashi Setsuna/Eas/Cure Passion
from "Fresh!"Aono Miki/Cure Berry
from "Fresh!"Minazuki Karen/Cure Aqua
from "5" "5gogo!"Yukishiro Honoka/Cure White
from "Futari wa Precure" "Max Heart"Akimoto Komachi/Cure Mint
from "5" "5gogo!"Misumi Nagisa/Cure Black
from "Futari wa Precure" "Max Heart"Natsuki Rin/Cure Rouge
from "5" "5gogo!"Yumehara Nozomi/Cure Dream
from "5" "5gogo!"Kasugano Urara/Cure Lemonade
from "5" "5gogo!"Milk/Mimino Kurumi/Milky Rose
from "5gogo!"Kujou Hikari/Shiny Luminous
from "Max Heart"Kiryuu Michiru
from "Splash Star"Kiryuu Kaoru
from "Splash Star"Dark Dream
from "5"(movie)Dark Rouge
from "5"(movie)Dark Mint
from "5"(movie)Tsukimiya Kaguya/Cure Night
from "Bouken! Precure days"
(fanmade,unofficial)Milk human form (fan imagined)
(fanmade,unofficial)Momozono Love/Cure Peach
from "Fresh!"Dark Aqua
from "5"(movie)Dark Lemonade
from "5"(movie)