Do birth and death rates in the family bible have value to genetic counselors?

Definitely yes. Any records of births & deaths in the family can be useful to genetic counselors. Extra helpful if any info on health status, cause of death, age at death, how many children & any fetal/infant/child deaths.
Sure. And to other counselors as well. Having a bunch of early childhood deaths recorded from "fever" or "flux" is the best advertisement for immunizations i can think of.