First up is Metamorpho. His original concept had the figure as having a translucent plastic helmet so more light would get in, but the 2010 release has an opaque grey costume. Solution? Swap in the glow-in-the-dark Alpha Phase Metamorpho helmet.
Next is Inferno. The original unproduced figure was to have light-up elements, specifically the head. Due to the enclosed helmet, this proves difficult. To give the figure a glow (after you swap in a translucent head, of course) he suggests you