I'm not sure you can do that directly in AE. Maybe there's a plug-in or something.
I'm pretty certain you can in Photoshop though. The fact that Photoshop will rasterize the pdfs should mean that you don't have problems with the fonts... although you need to make sure you rasterize at a high enough res so you don't see pixellation.
If you don't have Photoshop, then you could screen grab them.
I thought fonts were embedded in a pdf.... although I've also seen examples of missing fonts when opening a pdf in Illustrator. I wonder how it's saved and whether that makes a difference.