What country are you in ? Films can't be re-downloaded in all countries. Does the film show in the Purchased link under Quick Links on the right-hand side of the iTunes store home page on your computer's iTunes and the Purchased tab in the iTunes app on your iPhone and iPad for re-downloading ? If not then you will need to copy/sync the film over to them yourself.
Yes - but you should keep an maintain a backup of your purchases, as even for things that you can currently re-download (apps, ibooks, music), there is no guarantee that they will remain in the store for future re-downloading (content providers occasionally remove their items).