ANSWER: No. PeopleImport CANNOT be used to import Person Accounts. It is only for Contacts and Leads and will always require that an Account Name be mapped. The "Account Name" field in Person Accounts is a formula field which pulls the First and Last Name fields to create the Account Name and as such cannot be directly inserted or updated.
However, the MassEffect module in DemandTools can be used to insert Person Accounts. When importing, will need to map over the Person Account Record Type ID. The Discovery module in DemandTools can be used to determine if any of these records already exist in Salesforce before inserting. A condition to only match to Accounts where the "ispersonaccount" field is TRUE (or where recordtype = person account) will be needed when selecting which Accounts to match the input file to. The "Account Name" field cannot be used in the matching, instead use the first and/or last name fields. This will also allow the option to use the "FirstName" mapping type when matching on first names.
