Looks all compatible to me. My only concern would be fitting that big rad in a mid size case. But from looking at the case images. I believe it will fit.
Pick DDR4-3200MHz ram's/kits.
You could build it smaller if you don't intend to use the other slots on your motherboard. You would need a smaller motherboard apart from a smaller case.
IMHO, I would go for a USB driven WiFi adapter or a motherboard that comes bundled with WiFi connectivity.
Looks all compatible to me. My only concern would be fitting that big rad in a mid size case. But from looking at the case images. I believe it will fit.