IMO it is difficult, if not very difficult, to get crayfish established in a pond with adult bass present. To get them established one needs lots of their preferred habitat as cover, usually extensive rocky shorelines; heavy wood cover might work.

Bass and panfish love to eat all the various sizes of crayfish. Smaller fish eat the new crays less than 1" and bass eat the larger ones depending on the size of crayfish and bass. Crays around 6" long might persist as breeders with 18"+ bass present - maybe not? Again habitat is important. If bass can eat the largest crayfish then when they die of old age without adequate cover, who survives to create crayfish eggs and hatchlings?

Crayfish provide good plant control for several reasons: 1. crayfish density compared to plant density is important,
2. Crayfish as omnivores eat a wide variety of plant material,
3. As their density increases crayfish more disturb sediments making murky water as described above by QuarterAcre. Murky water reduces light penetration that limits plant growth. Less plant material feeds fewer crayfish. Murky water proportionally reduces phytoplankton production as the base of the food chain. This limits natural production of fish. It is all a matter of balance.