Hi, sorry, I have completely missed this thread for some reason...
CEGUIFalagardWRBase.lib was renamed, now it's called CEGUICoreWindowRendererSet. (Which makes no sense, I have no idea why we named it Core... Probably a rare mental weakness in the CEGUI team. Have to check this)
regarding setGUISheet, 0.8 has a new concept called GUIContext, it is described in porting tips.
I think tooltips no longer fade with custom C++ code but with XML defined animations instead. You can change the animations to whatever you like in your looknfeel. (Even make custom animations that don't just fade)
Not sure about setSelectionBrushImage, Images are now referenced with "Imageset/Image" instead of "set:Imageset image:Image".