Am trying to override standard Owner Field label on Managed Package Object using Translation Workbench Override but the field is missing from Translation workbench and also we don't get an option to rename Owner field label from Rename Tabs and Labels.
This is not possible as of Summer 2016.
Currently the Owner field on the Standard Objects can be renamed but not on the Custom Objects. This should be extended to the Custom Objects too.
https://success.salesforce.com/ideaView?id=08730000000l30NAAQ
https://success.salesforce.com/ideaView?id=08730000000Y4X5AAK