They will work but maybe not perfectly. I only guess this because I never updated OreoSlice and its in the toolbox already and I'm using another theme I made for Liberty 1.5 on 2.0 right now.
As for the themes josh they are in "ROM Manager -> select the dropdown menu -> then select themes -> download all roms. It should then load up a list of the available themes.
The GUI is a bit different now but I think it offers a lot more features for us to use.