I think they’re pretty comparable in terms of damage; Litchi used to be pretty stupid, but she got toned down a bit in this release. I’d probably rank it
Rachel
Litchi
Lambda
But that’s not very objective. It’s mostly just based on my vague feeling of “how often can this character land a big damage starter” rather than anything else.
Lambda is definitely the weakest at rushdown of the three of them, but she still has some very good ways to set up an approach. (Usually sickle-storm oki, though she also has a super she can pull out to basically say “and now I get to rush you down and mix you up.”). Rachel has the shortest range normals of the three of them, but has “the pumpkin” which can often provide her with an easy in. Litchi is the most standard of the three of them, but she’s pretty freeform for all that.
I personally think Rachel is the hardest to learn, since her Sylpheed drive is kinda confusing and really not like anything in any other fighting game anywhere, so it can be tough to wrap your mind around. She’s also the only one of the three that has to play any sort of additional ‘resource management’ game (unless you count Lambda’s gravity seed meter). Litchi is probably the next most difficult to learn and play correctly, though I think her learning curve is more even than Rachel’s - Rachel is going to be really hard at first while you figure out her drive, then it gets a bit easier, whereas Litchi’s drive is more straightforward. Lambda is probably the most mechanically simple of the three, but that doesn’t really mean she takes any less skill to play effectively, since she requires a much better sense of how to control space in the arena than the other two.
All three characters have potentially strong payout and have all the tools they need to win but none are top tier either.
I can’t really judge their normals - there are too many factors, I think. If I REALLY had to guess, Litchi probably has the best, followed by Lambda, followed by Rachel, but Rachel uses her drive to improve her normals in a lot of ways, so as long as she has wind… it’s not simple.
The one other caveat I feel I should mention is that they just announced and are testing an all new BB game, and right now, it doesn’t seem like Lambda (or another character with the ‘Murakumo unit’ playstyle) is in it, which makes no sense on a lot of levels, and we’re expecting that to change… but right now, she’s not in.