1) IIRC (hadn't have first hande expierence with DelphiX for a long time) doSelectDriver option forces popping-up dialog box asking user for preferred display options.
2) I don't remember any 'DirectX7Mode' option - probably because it's UnDelphiX property.
3) Surely do3D is valid option for DelphiX - it means what during initialization of DirectDraw - Direct3D part is also requested/initialized.