1 - Yes you can set any ringtone you want. Use the ActiveSync software supplied with the phone, to connet to your PC and copy the releavnt files. If the file is not Mp3 or WMA format, its not a problem as the phone automatically converts the file to a suitable format, which is handy.
2 - I personally think the device is mechanically sound, else it would not be feasable for commerical release.
3 - Use ActiveSync to copy the file to your removable memory card which I assume you have; to the Videos directory and play from within FileExplorer or WMP.
4 - Yes. The device may be able to convert the files itself, however this may not be possible for all filetypes!
5 - I belive remote printing is supported. Read the manual provided with the phone.
6 - No idea. Should not take long, seeing that you have a 400Mhz processor!