Yes, it allows you to encrypt your migrated file with password protection.
This software has demo and full version, demo version is completely free and has all the features of full version but it limit you to migrate and save only first 20 items from each folder of GroupWise to MS Outlook.
No, it is not mandatory to split the file after migration. You can migrate complete data into single PST file.
Yes, GroupWise to Outlook converter allows you to set file size but it does must be set in range of 100 MB to 50GB.
This software is buoyant tool and needs only 50 MB free space on hard disk.