You and your sister look very ethereal, expressed via brightly toned hair with slick arrangements (dunno if they're wigs or actually dyed, still beautiful), + based Gothic casual and bright lighting amidst crystal clear forms. The lighting, while sacrificing glaze touch and gradation in favour of soft exposure, helps make hair colours pop, skin-tone vibrant in an aura-like feel, and intricate light plays onto spellbinding, jewel-like eyes. Also a wise choice to avoid any expressive/loud form of smile or expression, the ambiguous helps balance out with the colourful exuberance and one will be captivated eye-wise because of it.
I never expected this. Asides blowing your other twin portrait "ArcX Light and Dark" out of the water, this is a marriage of both your honed "Alternative" & beginning "Positive" styles; seemingly simple at first impression yet completely defined.