Natural light would be a mistake, because over the course of the hours it will take you to do the animation, it will change too much.
At the same time, duplicating an “actual” bright sunny day might be garish, with deep shadows. It sounds as though you want the “feel” of a bright sunny day, i.e. an upbeat, sunny, summery mood, which in Hollywood involves silks and HMIs. That could mean either frontal lighting, or heavy backlighting with lots of fill. Just avoid “high noon” lighting — i.e. keep the lighting sources lower.
I’d experiment, if I were you, with whatever instruments you can afford. I’m guessing that for the bright mood you seek, you’ll want is to have one big but lightly-diffused key from near the camera and a sharply-focussed hairlight to make the characters stand out from the background. Just avoid multiple keys, as the shadows will make for a very inauthentic mood. If all you afford for the key is a bunch of broads, pump them all through a big silk.
You didn’t say why you disliked the other videos, but whatever they did – don’t do that.
bob c