Indoor HDRi scenes and the ground's relationship to characters/props?

RenderPretender

I have been doing a lot of reading here on HDRi and have actually had some success with them generally. But in using Apocalypse Indoor Scenes, I am having more trouble than usual getting the character(s) to appear to contact the ground convincingly. Draw Ground is on and catching shadows, but am I supposed to be moving the characters down on the Y axis, or moving the ground origin up along it? The matter is complicated further by one character being shorter than the other, and having different footwear (sole thickness), so it's a nightmare to get them both, as well as props, to absolute ground zero in a convincing way.

Also, i have noticed that when I try to rotate the camera around the characters, they wind up in a different place in the room. Am I supposed to be rotating the cameras/adding new cameras, or moving the characters along X or Z? Rotating the dome changes the whole environment so that's not the answer.

Suggestions wil be memorialized in my bookmarks.

Thanks in advence.

RenderPretender

Ah, just re-discovered Ground Position Mode. I set it to manual and that helped, but I think I'll try setting a small utility plane at zero to assure that the bottoms of the characters and props are all at the same Y location.

Still befuddled about the rotation/placement of characters in the scene.