For each bathroom choose a neutral color that U see in the tile Here is how to find the perfect wall paint "match" http://www.lindaholtinteriors.com/2011/07/testing-wall-color-101/

do you have the interior designing and finishes finalized? as I mentioned earlier, everything in the room has to be tied together. I cannot give you a colour for the arch if it is going to clash with the window frame job, or the cabinets or the wood. In case you don't, I can help you with that. we offer consulting services, which is basically this, the help on Houzz, in a lot more detail. If you are interested, please connect with me on 9921364291 miloni The Yellow Cushion

Either, you can paint all the walls with light grey or white colour. Or, highlight one wall with light grey colour and rest of the walls can be white.

Hi,  An oversized painting / wall mural / traditional wall art (you may choose state specific on this one) should highlight the volume and height of the space. Additionally, good lighting - wall scones / chandelier will add to the beauty. Hope these tips help!  Regards Ar. Manjusha Adhav - Kamble