With regards to you first post - Embree.
It is an acceleration engine I believe originally developed by Intel, but it cant' handle lines points etc, which is effectively what foreground wireframe is (even if it looks 3d), so if either of the foreground wireframe options are ticked it will show the warning (unless one ticks don't show it again), according to Redway (RedSDK) having part of the drawing using RedSDK Kernel engine and part Embree can slow things down, so it looks like the programmers turn it off to avoid this happening.
Redway info on Embree http://www.redway3d.com/downloads/public/documentation/bk_re_ray_tracing_options.html
about halfway down the page.
With regards the render, Just to add to Torfinn's comments, this happens in any mode whether Lightworks or RedSDK and is done to speed up changing views like rotating the view using the mouse, you box renders pretty quick, but some renders can take 30 seconds or even 30 minutes to complete, so moving the view would be extremely slow.
With regards Displacement mapping, its a feature of the material properties that you won't have used in the drawing - see Displacement map - http://www3.turbocadcommunity.com/tiki-index.php?page=RedSDK+Displacement+Map
, the option is available when editing materials and uses a 2D image to alter the look of the 3D object when rendered.