Yes, it is possible. However, you will have to make separate requests using the
Parallel Report Download per each report type you wish to generate. As for getting the
all time records, you can simply choose not to specify a dateRange in your SELECT query. You may note however that should you include a Date field in your query, you will be required to specify a specific dateRange as discussed
here.
In addition, you should also take note that retrieving all time records might cause
timeouts due to the volume of data you wish to retrieve and since you plan on generating for all accounts, your developerToken's access level will need to be at
standard access level if the total number of reports you will generate during the day would be greater than 1,000.