do melee next and add a prop (or scripted weapon) that's just fox's gun.

I really think this platform is just too large. It's a cool concept, but you can't even get close to looking over the sides with its current scaling, something I think should be a part of this environment.

I haven't seen it yet (slow internet) but it should be large enough to have 3 people standing shoulder to shoulder between the narrow part

That's how I did it. Roughly 4 normal sized people should fit on it, so the proportions should be somewhat ok, but it just doesn't feel right. Maybe it's just since you're actually seeing it in first person and not from a distance tough.

You do have a reference point, don't you? LoZ characters are more-or-less realistically proportioned; take a reasonable guess at Zelda's height and go from there.