You can use collision detection and move your figure down to the floor (as long as you have an object for the floor -- a plane or cube or whatever), but there is no CTL+D like in poser.

As for the sky issue, I suspect you're dragging a sky from the browser into your scene.  Those skies in the browsers are entire scenes, not just a sky preset or something.  So, if you drag a sky scene into an already existing scene, you're going to get the extra components of camera and light.  You also may well end up with a number of parameters (render settings, etc).

If you select your whole scene, then under atmosphere on the right, you can select sky or realistic sky and edit appropriately.  There are presets within the sky editors.

Hope that's helpful.

 - Dex