If you will be doing business in the Dominican Republic, you should consult with a knowledgeable lawyer. Money spent on legal advice will be savings because you will avoid getting into costly labor cases.
To answer the original poster's question about hiring without a cedula… Yes, US citizens can be hired without cedula. You could ask about the Business Visa. This would make legal foreigners working temporarily in the Dominican Republic.
You can download more information on the Dominican Republic Embassy in Washington, D. C. website
Business Visa for employment purposes
DESCRIPTION
Business visas are issued for work purposes to those who by nature of their occupation will remain in the Dominican Republic for a year without necessarily having to leave the country. This visa is usually awarded to individuals who are fulfilling fixed-term contracts in public or private companies established in the country and may be renewed for further periods of one year while the employment contract is still valid. Beneficiaries of this visa can apply for driver's license, open a bank account and enjoy applicable customs facilities.
http://www.domrep.org/visa.html