You can use videos as textures, but it is ill-advised, and there's no obvious cut-scene access in the game.
Each video takes up an enormous space in video memory, especially a high-quality, full screen cut-scene - so much in fact, that you'd either have to cut the resolution ad length drastically, or better, not use it. In order to play it, you'll probably have to place a quad over the player view and use the video texture.
create you very own in game cinematics. You can use matinee to animate a camera and kismet to trigger cinematic mode and use the cameras as you need. Not hard but tedious work, though in the end, very effective.