Is it possible to have a separate owner for each schematic sheet. So that only one person is able to edit/make changes.
This question is related to multiple engineers working on a schematic?
How do multiple engineers update/edit the schmeatic.
Is there a version control with diff available ?
Not really in all cases.
You can get a "master" schematic made from hierarchical blocks defined by external schematic projects but there is no real sens of ownership since Capture is really aimed at "personal productivity" rather than "team design" (there are other Cadence tools for this activity)
There are some design comparison tools in the Capture Marketplace but you might need to get a later version to fully take advantage of them.