I'm not sure why mITX was chosen - in my experience it's almost always more expensive and leaves no room for additional GPU expansion (Or network adapters/whatever card you might need) in the future. You can get 1151 mATX motherboards for more like $60-70 on Amazon instead of the $125 they paid.

Also, paying $125 for 16GB of ram but not spending the extra $20 to have your CPU be able to overclock? I'm not sure where OP is building but I can find that much RAM for $20 less than they paid, and overclocking isn't really that difficult or unreliable these days.