Aalwein,
You need to replace the image used for no 3d portraits option with an invisible one. Means you have to deselect the 3d portrait option.
Also you can either do the same for the vitals skins or use a small layout around the bars only.
The only thing you should keep is the level background as you can't move it around.
It's been long time since I put my hands on the UI so might be better for you to check my stuff
