If you want the see-out-but-not-see-in effect, for daytime use look at mirrored window films. If you go that route and that will be the only treatment used, mirrored films give privacy to the side of the film that is darker. Typically in the day time people won't be able to see in, but at night when your bathroom is lit up and it's dark outside, the effect is reversed...you won't be able to see out but people outside can see in. So while that type of film is good for daytime, you'll need to couple it with a curtain or blind for night time. Or you can go the route of a frosted film. You'll retain some light transmission, but lose the view. There are numerous styles of frosted films, and the amount of light they allow to transmiss does vary. There are stained glass films too if you want to go decorative. That aside, for window shades, I like top-down-bottom-up for any actual window shade. If you're not familiar, with those shades you can lower it from the top (usually most effective in a bathroom), or raise it from the bottom, or both. If you can lose a little of the view and natural light during the day, then go with just a T-D-B-U shade. If you want to preserve the entire view, your best bet will be to use a reflective film. That'll give you privacy in the day. Couple it with a shade for night time use. If the view isn't important and you prefer to not have a window shade, than a frosted or semi-opaque film could be used. Color recomendations, I'll leave that up to the stylists.

If you have white wainscotting and oak trim and floors, I would hesitate to go with a taupe or stone color because in my mind oak is naturally more on the yellow side of things while taupe or stone would be more blueish. I know you said you have blue walls...but the way I imagine it doesn't look right. White or just barely off-white, in my opinion would look better, although without a picture I can't say for certain. And, for the record, taupe is my favorite neutral, so it's not because I don't like the color! I think roman shades are the way to go here. Would the smaller window look silly with roman shades (is it too small)? You could also think about cordless honeycomb shades, which would let in the most light.I don't like those window films - I think if people look in they can still see through them somewhat.

Overall what you have done is fairly neutral as far as color goes, but you do have a style selected in the mirror and light fixtures (and manicure LOL!) Go with what makes you happy. I have probably bought and returned about a dozen shower curtains before I've said "wollah - that's it"....but buying from someone on eBay makes that a bit more problematic.

It would be a shame to cover those pretty windows. If absolutely necessary you might consider cellular blinds that almost disappear when raised.