A life insurance policy must pay a death benefit based on the policy. An insurance company may deny claims within two years after the date the policy is issued if there were material misrepresentations on the application.
Yes, if the denial is based on their underwriting guidelines and the guidelines comply with North Dakota law.
No. Your disability policy will only pay if you meet the definition of disability in the policy and have satisfied any elimination period. Review your policy closely as there may be various details around elimination periods and how long you are out of work.