An Easy Setup is a group of standard settings for video & audio: frame size, frame rate, video codec, audio, etc. When you create a new sequence, the sequence settings are determined by the currently active Easy Setup.
When I choose "export > quicktime video" the result is 720 x 480 which is not "wide".
This is because your Easy Setup, and therefore the Sequence you created, is the default "DV-NTSC" easy setup. You have already figured out how to change the Sequence settings on an existing sequence.
That said, I noticed you said your source material is QuickTime ProRes 4:2:2. FCE does not actually support ProRes ... you may be faced with a lot of rendering while you edit, and your results may be unpredictable. FCE officially supports Apple DV and Apple Intermediate Codec. Final Cut Pro (as in Final Cut Studio and Final Cut Pro X) support ProRes. For best results with FCE you should transcode (convert) the ProRes 4:2:2 material to QuickTime/Apple Intermediate Codec. You can probably do that with MPEG Streamclip. Before importing the material into FCE, set your easy setup to one of the AVCHD easy setups that matches your frame size & frame rate.