Dear CH,
Actually you could add some comments to a specific entry on the designers' page by clicking the logo (entry). This way, the designers would be notified by email that you've add any comments on their design page.
But, generally speaking, yes you could get the final files from the winning entry in several file formats. And technically, it would be in two different file formats (.EPS and .JPG). But you could also ask the designer to give you different file format, such as .AI, .GIF, or another file format that properly fit to your need. And you could ask some tweak changes from the winning entry regarding the layout, alignment or color combination, but not the basic concept.
Thank you,
Best Regards,
Sunardi
Logo Designer