Just change the CPU from the i5-6500 (6th-gen Skylake) to the i5-7500 (7th-gen Kaby Lake), faster speed CPU, for almost the same price (~$1 difference). 7th-gen CPU works best for that B250 motherboard you selected.
The rest is okay. Just make sure your "missing parts" are compatible with the ones you listed, i.e., DDR4 RAM, case size/clearance for CPU cooler.