The Arctic i32 isn't enough cooler for an i7-8700k. It'll do the job, kinda the same way most cpus have a stock cooler, but don't expect any real OC or hard usage such as rendering or the fan on that arctic will be screaming and temps will be very high. I'd strongly suggest a Noctua NH-D15S if sticking to air coolers. While Corsair specs say 156mm, there's no issue with 160mm, and can even get to 170mm although 171mm hits the window. According to reviews, the specs really don't match the case, you can stick 3x fans in front, just shift the 2x pre-installed fans up. (or down).
Other than that, all you seem to be missing is the really expensive component, the gpu and possibly an SSD for the Windows drive. (helps considerably)