These forms are unlikely to apply to most beneficiaries that are paid by businesses.
In general, the W-8ECI is used for special instances in which a foreign individual receiving nonbusiness income would not be subject to the 30% tax as in forms W-8BEN and W-8BEN-E.
Instead, the individual would be taxed at the same graduated rate as US citizens.
The W-8EXP is primarily used by foreign governments, foreign tax-exempt entities, and any US possessed or foreign central banks.
If you believe your business may need to use these informational forms, please contact our in-house CPA for a consultation on your specific business situation.