ERISA doesn't apply. State insurance laws don't apply (it's not insurance). COBRA, HIPAA, etc. do apply.

But is the basic law governing self-funded governmental plans simply state contract/state employment law (subject to the authority of the entity to establish such a plan)?

Are there other considerations?

Basically, yes. However, you would also want to keep in mind any nondiscrimination rules, such as those which apply to cafeteria, flexible benefits, and pretax premium arrangements under Internal Revenue Code section 125.
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