Yea, I got that from your plan.

choose a bright color theme only for one wall say blue or indigo, rest can be light or white tiles.

Second option is you can go for light wooden finish tiles in the bathing area, divide that with glass partiton and go for the matching combination for the rest of the walls.

Go for compact vanity with a mirror frame that goes with your vanity design.

Take care to provide good light as you don't have natural light.

You can use brown tiles for the floor that are anti skid,the wc can be on the wall mount to free up space and maintain cleanliness,space blue color from the ceiling to center ,dark blue pattern in the middle and darker blue at the floor level.vanity and mirror to be fitted at a place where light falls on the face and lighting above the mirror for being able to see clearly.