Hi,
For your first issue, if you do not use a filter it will return only the last run, so you would need to get a list of all the jobs with that prefix and then loop through them. Which may not be a bad thing as for your third problem if you use the 'job' endpoint instead of 'job-run-info' it will give you the jobs with the prefix you supply, but also has the answer to your third issue, the current status of the job.
The second issue will depend on what release you are running. In the 12.0 release a new endpoint 'jil' was created and when you use a GET, it will give you the autorep output for the job. If the job is a box, it will give you all the jobs within that box, it does not have a level 0 type of parameter that I am aware of.
Regards,
Mike