Dunno if this was post before, on your iphone go to iPod, instead of selecting video, you click playlist, recent added and play the video from there, you can play in both potriat and landscape mode, dunno if that's a feature or bug.
That's something completely different. You are adding it in iTunes but it's not on your iPhone at all? If you can see it on your phone, you should be able to play it in portrait mode.