I quite like the old fashioned names for guineas. Since these guys are black and white how about Betty (boop) and Minnie (Mouse).
Or maybe something along the theme of opposites since one is black and the other. Day and night perhaps? Luna means the moon, and Solana (and all similar names) means the sun.
I always like names after plants too eg lavender, parsley etc but perhaps not for black and white guineas?