I know something about VBA (Acrobat Interapplication Communication) and can guess something of the Adobe PDF Library.
My point of view is that VBA (Acrobat Interapplication Communication) is using Acrobat and can't work without it.
If I well remember, some commands can be silenced so that Acrobat stays close but they normally require Acrobat to open up. I don't think the .dll library alone is enough to make VBA code work, though I am aware that the only thing we need to configure in Excel is the .dll import.
I guess the same is true for the Adobe PDF Library.
Well, not exactly: Adobe PDF Library SDK | Adobe Developer Connection
and here is a diagram: as you can see, the grey part (PDF Library SDK) exceeds the orange (Acrobat SDK). That extra area represents PDF editing without Acrobat and Server apps.
About silenced commands: it depends on the layer you are using. I guess the Document and Cos layers are silenced by default.