well I main both characters. Litchi has to space Bang out with her long pokes. For example, standing B, Jumping C, Crouching C(anti-air). and then lead those attacks into combos.
I've played both side of the coins here.
As a Bang player, Bang are going to try to rush you down. Sure you have to Tsubame move but it is relatively unsafe and a smart Bang player is gonna bait it by blocking up close at times.
litchi player has to keep Bang out. Spacing is absolutely critical in this game but for this match-up, it is very critical. Otherwise the Litchi player will fold because of the up close pressure of Bang.
Generally, you want your staff in your hands for her long range attack.
Also it is good advice to not burst at certain times as Bang drive can easily counter it.
In CS, keep away becomes more critical as Bang is faster, safer, and stronger. On the other end, Litchi is strong as well.