For a graduation, I would suggest #5, but change the accessories. How about a mid-heeled shoe in blue, black or metallic? And how about a necklace in metallic or one or more bright colours? If it is cold, you could wear the dress with a light woolen camisole, opaque hosiery in blue or black, and a colourful scarf.
Anyway, I vote for a dress/skirt outfit. This will be a very special occation, one to remember, so allow yourself to "stand out" (in a positive sense) with a feminine outfit in bold/bright colours. You look so great in skirts and dresses! And there will be countless other occasions for wearing trousers and neutral colours.
The offwhite skirt is very beautiful. As there is "a lot going on" in the skirt itself, it will often look better with solid coloured tops than with patterned ones. I think you can wear the skirt with many colours. For a graduation, it would be elegant with an offwhite pullover/sweater or blouse. Or you could wear the offwhite skirt with a top in different colour, say a silky blouse in brown, cobalt blue or red (perhaps with matching shoes), and then, for a casual elegant look, wear an offwhite cashmere/pashmina shawl around your shoulders.
Actually, an offwhite shawl would look fab over many other outfits too, (including your cobalt blue dress) and be useful for many later occasions as well, year round.