Outfits
Since Shiina is only in the two anime episodes we only get to see her in a couple of outfits -- her real form and her human disguise.
Normal Form
Princess Shiina's first outfit covers her entire body (as no one is supposed to see the bare skin of royalty). She wears a pink visor that covers her eyes. Her main outfit is all red with pieces of pink around her chest and abdomen. Her boots are also pink.

Human Disguise
Shiina's human disguise consists of a long sleeve yellow dress, a pink vest, a white bow, thigh-high white socks, and pink shoes.