In truth, resolution means nothing when you're creating graphics for video (or for the web), MJK. Most people use 72 ppi as a matter of convenience, but it really doesn't matter. The measurement, in pixels, is the only measurement that matters when creating on-screen graphics.
As for bicubic sharpening, that's a matter of preference. I always use the bicubic sharpener when I'm down-rezzing photos. It makes for sharper image. But, when down-sizing photos for video, it may not matter. Might be worth experimenting to see if you can see the difference.