You are going to have to leave your comfort zone on this one. Walnut is "brown", you have "pink" as a counter top. I would suggest going with another version of the colours already in the room. you have gray/beige and white. I would hesitate going white...but it can be done. You can move into the grays and be very happy (it would look very modern) or you can move into a beige that holds a hint of pink in it (not pink...but a blush of warmth). Or you could go really wonky and add in something like a brushed stainless steel look to the cabinets and have it go "space age". There are specs of blue/gray in this counter top. The next think to look at is an "ashwood" or dark gray wood presentation that has some blue in it. It would lighten the space yet still add drama that dark cabinetry offers.

Is it burgundy granite? I think we need to see it. I like gray with burgundy.

I have used both with good results. The main difference between Quartz and Granite are 1) price, 2) colour range. Granite generally works out cheaper, because you can buy the exact quantity you require. Quartz comes in large slabs of specific sizes- standard size being roughly 10'-0" x 4'6", so there tends to be more wastage if you don't plan the cutting well. But Quartz is pretty and comes in a wide range of colours and can be re-buffed at a later date. Quartz also comes in various thicknesses- the most commonly used being .75" to about 1.25". And especially when you use dark wood cabinets in a kitchen or bathroom, beige and white counter tops work very well. Some people go even with coloured counter tops like blue, orange, yellow. Natural stone in light colours tend to be porous and stain easily, so I prefer to go with pure black which is safe.

the sink should be at 33" from the floor. your countertop height will depend on if you're using a top mounted or insert sink