Well, to use CI it's probably best that you don't use workflow, becuase it will only track a change when you hit publish, and by default with WOrkflow when you are editing it will show the current workflow step.
So the scenario where you have Create a Document and Publish (Say "Version 1"), and you then edit hte document, it's pulling from the Workflow. When you import from Continuous Integration, it overwrites the "Version 1" so to say, but you still have the Workflow step.
If you want to keep workflow, you may want to write a script that either checks in or cancels the checkout of all pages before doing an import, so that way there is no workflow step, and it will set the imported content as what you have.
You do not want the developers to use a shared database, as the changes need to be tracked on each computer so it can make the CI information for the change.
One question you should simply ask is "Is continual integration vs. versioning the way to go for my situation." CI is an option if you want all your database changes in a Code Repository so you can do pushes, changesets, etc. But you lost a lot of functionality with it.
Having a Shared database and just using built in Kentico versioning is great if you don't need the code repository, downside is everything is in the database. I've only used CI for our Custom Development Kentico instance where we create tools that we use on other sites.