Although the sales pitch on the Apple website tells me I can now have a unified library, Aperture still asks me to switch to another library. Obviously they aren't unified.
what is your iPhoto version? And when exactly is Aperture asking you to switch to another library? What exactly is the error message that you get?
To be able to use a unified Aperture/iPhoto library, your iPhoto Library needs to be upgraded to the new unified format. This requires opening the iPhoto library in iPhoto 9.4.3 at least once to convert it. Have you upgraded iPhoto? Your new computer with SSD should have come with iPhoto 9.4.3.
Unified library does not mean, that the libraries will be united, unless you merge the libraries. It means, that the libraries of both applications are compatible and can be opened by the other application. Also, you should be able to import your iPhoto library into your Aperture library and merge the libraries. See these support articles:
Before importing your iPhoto library unhide all photos that may be hidden. Aperture cannot unhide the hidden photos.
To avoid importing duplicates use the "merge" option, when importing the library, not the "add" option.
In addition, I have hundreds of duplicate photos in my pictures folder where I have exported photos to use in a Wordpress blog. Any thoughts as to how to delete those duplicates as well?
As for the duplicates in your Pictures folder - are those all duplicates or are some of them images that you need to keep? If they are all duplicates, why not make a backup of this folder and delete the image files using the Finder? aperture will not be able to recognize them as duplicates, if if you renamed them when exporting or resized them.
you need to contact the App Store Support.
There is a link in the right panel on the main page (in the "Alles of einen Klick" panel in German).
The problem is, that the preinstalled iPhoto has been accepted for your computer to a different Apple ID, and the App Store does not know that the mac now has a different owner. They need to remove the link to the previous Apple ID.