Here are the basic essentials for batch jobs, we can start with this and then answer other questions as they come up.  I have a java unit test written that runs a series of batch job operations that I can send if it would help as an example.
 
First create a list of users that conform to the User.xsd, then POST that list of users to a URI like the following:
 
POST http://<server>/vmrest/users/batch?op=POST&templateAlias=voicemailusertemplate
 
If the POST is successful, the response from the POST is a URI that identifies the batch job (batch jobs run asynchronously).  The status of a batch job can be retrieved using the returned URI as follows:
 
GET http://<server>/<uri returned from POST>/status
 
The status will be a batch job status object as defined in BatchJob.xsd.  When the batch job status indicates the job is done, the results can be retrieved using a uri as follows:
 
GET http://<server>/<uri returned from POST>
 
The returned results will be a set of BatchResults as defined in BatchJob.xsd.  When donw with the batch job, it is good practice to delete the batch results using a uri as follows:
 
DELETE http://<server>/<uri returned from POST>

Due to internal implementation issues that we could not tackle in the 7.1(3) or 8.0 timeframe we do not currently have the ability to configure or manage LDAP imports via the API.
 
To detect whether a user has been LDAP integrated, it is possible to check the LdapCcmPkid field on the User.  If it is not empty, the user is LDAP integrated.  But this would be a per user check, there is no direct way to pull just the users that are LDAP integrated.