Reginald,
1. Check the sharing area of the forums for a custom item that measures some standard demographics. It is HTML (!) but you can edit it in a text editor--the changes you will need to make should be minor but feel free to ask us to help if you run into trouble.
2. Do you want true random (probably resulting in unequal n's), or an equal number of each movie across conditions?
3. Just add the questions at the end. Number them to fall between the items where you wish them to appear--e.g., if between 3 and 4, then number then 3.1, 3.2, 3.3, etc. Press SORT and then RENUM. It's a method used from OLD days of program coding. Check out the section in the guide on question numbers.
4. Select the "Movie" item type and enter the file name of your movie in the file name field. Or do you mean how to play .mov files that don't seem to play when you do that?