I'm painting and faux painting someone's bathroom and her tile is blue with a burgundy border tile at the top. She wants to make the base coat sort of a light burgundy and she wants me to sponge on true dark burgandy. My question is, what other lighter colors would go good instead of these very dark and gloomy colors in a small bathroom.

Thank you

I think a yellowish tan would go nicely with the blue and burgundy.

I'm an interior designer and would recommend painting the base coat a ice blue and ragging a white/blue (in the white paint selections there are whites with color tints) over it.
Make sure to add glaze to the top coat :50% glaze and 50% paint. There is also a technique called frotage which can be achieved by taking a large piece of saran wrap (crumple it up, then open it up and lay over the glaze/paint coat - then remove and repeat (you can also use crumpled paper) Good luck!

Pale pink does well with burgandy if its in the same red to blue ratio as the burgandy is. Hard to say how well it would go with the blue without knowing the shade of blue. Then the blue can be picked up in the accessories. Pink makes for a nice ambient light in a bathroom too, which helps if one is applying cosmetics in there too? If you aren't sure, purchase a pint can and paint a patch to test it.