Answer:How shallow is the depth of your windows? If 2" blinds only slightly stick out of them when open and if you satisfied with their look, it is OK to install them inside mount. I suggest you to request a sample of 2" wood blinds (or, you can make a 2” cardboard stripes instead) and see how it looks on your windows. As alternative, you can install outside mount 2" blinds, but they might take a large amount of your room’s space.
As for blinds color, I don’t think you need to match it exactly to the walls, but if you doubt, you can ask for free color samples and check their look.
A valance hides a headrail mechanism and gives a complete look to your
wood blinds. I highly recommend you to get it. Please note that if you decide on inside mount 2" blinds you will need to install outside mount valance for them for more aesthetical look, otherwise they will stick out of the valance when open.
Hope it helps,
Alina