Include comprehensive sickness insurance only when mandated by EU rules, and in any case it's only needed for residence card application when you will be exercising treaty rights on a self-sufficient basis. You can open a joint savings account, perhaps off-shore.
We have joint account but it is an account in the Philippines and only small amount. We have an account here in Spain but and individual account because we cannot open a joint account here in Spain coz I am non resident here
As I said, I don't know how relevant insurance or joint account is for EEA family permit, provided you can evidence durable relationship in other ways, such as photos, trips together and communication record.