Adding more setup options to DFR is not planned, but you can set the compression format just from the filename input field. DFR will automatically choose the right compression method from the file extension, so there is no need to click the file type drop down list.
The compression progress window is displayed as a modal dialog. Making the program minimizeable while showing a dialog window would require bigger changes, so I really would like to set this aside.
I haven't tested DFR on Windows 8 yet, but I haven't heard of any general problems running DFR under Windows 8. So I think DFR should run under Windows 8, too. So with this little information ("I'm getting access violations") I can't help you. In the past the most problems running DFR were not raised by DFR itself but my some other programs, for example by programs trying to change the system GUI etc.
If you have many and large images in the screenshots folder, creating the thumbnails on slow systems can take some time. If this is true for your system and your set of images, you can try to change the image scaling method to some less resource intensive one on the user interface->scale images page of the program configuration dialog.