I have attached my first effort I used the database link to access the database and then used NiKolay's back sync to sync data back. issues are that the experience is a pretty ugle one.
1) you can create new objects and have them be created in your database so you have to create your objects in the database first
2) the shape data governed from the database does not have drop-down values that are the same as those in the database. The only way id be able to get the list values would be to create a data set and then i'd have to populate by hand all of the drop-down values.
Of course, the experience would be pretty ugly

When you connect to a data source, Visio has no idea that some fields are backed by dictionaries in the database (like your"Object Type"). So it generates default (string) fields. Therefore you don't get any dropdowns. In principle, generating such dropdowns is possible, but you don't get that "for free" with Visio. Since Visio is thought to be data *visualization* tool (i.e. you visualize your database content in Visio, not enter the data)
People who need to enter data, usually build their own (VBA?) forms, or design shapes to have those dropdowns..
You could also use SharePoint as a backing repository. So that it is all online in one place with basics (document storage, co-authoring, reviews, version history) set up. No need for home-grown document locking. You could enter data in a form with dropdowns (if you link shape to a SharePoint list item). You can even edit layout online now. Isn't it an option? From access database you can go there directly, there is a button "export database to SharePoint"