Vectorworks has a "silent" installer mode you can invoke (and I believe there's some documentation online in their knowledge base), but historically it's always refused to run while at the loginwindow, because it still depends on a GUI framework. If you need to install it in that context, your only option may be to manually repackage.
As of I think 2013-2014 versions they also pulled a couple things out of the installer and moved these into "first run" actions that prompt for an admin password, requiring even more steps to parcel out yourself if you _were_ otherwise thinking of trying their silent installer.
There's a Quicklook plugin, and all the content libraries are custom archives that have to be downloaded and "installed" using Vectorworks itself. You may need one or more of these content libraries if your users depend on them. These items used to be part of a single monolithic installer that resulted in a complete installation with no "first run" steps, but as of 2014 they were split out.
I also recommend (constructive) complaining to Nemetschek that deploying their software is extremely time-consuming and error-prone when needing to be done repeatably and at any scale.
Tim