Does the front basket need the front rack to attach to the Packa?

No, it does not! The front basket is designed to attach to the head tube on the Packa by itself. This is a part of the Packa's convenient plug-and-play design which gives user limitless possibilities for assembly and use. 

Can the Front Basket attach to the front rack if desired?

No, it cannot. Both items attach to the headtube, allowing only one or the other on the front of the bike at a time. However there are so many options for assembling both accessories onto different parts of the bike, allowing for use out of both at the same time.