Having played Litchi, I can say first off that Litchi's Rachel-specific combo is way worse than her regular combos damage-wise. Damage scaling hurts the loop a lot. Just sayin'. *shrugs*
Second, imo Rachel's best bet is rushing down, Litchi has way fewer options here than in neutral game. Just watch out for Tsubame, but when Litchi does throw her staff away she then has no defensive options whatsoever.