I like more the second build, i really would love to build on a node 304.
On the CPU i like more the i5 4670, its $20 difference most of the time, but has higher base clocks and higher turbo, weather its worth the extra $$$ its up to you.
On a build like your planning, the Asus mini itx is ideal in terms of the cpu socket placement, Asus mini itx from ivy bridge and haswell allow almost any cooler to be installed on them, i seen twin towers and still fit fine, even with a gpu.
Now my suggestions on the build are not money friendly and im going to suggest you spend a llittle more, weather you need it or not its up to you, but this is how i would have builded mine, disregard my suggestions if you planning on using the the built in fan controller on the node304. The H87-Plus only has 2 fan headers (CPU_FAN and CHA_FAN), the case has 3 fans, 1x 140mm and 2x 92mm, but they are different not only in size but into the range of operation. For this reason i would chose a fan that its similar to the CPU heatsink fan, so i can use a Y adaptor and run both fans from the same header (CPU_FAN), and i would also get a Y splitter for two frontal fans and run them both from the other header (CHA_FAN), this will allow you to controll all 4 fans with 2 headers and use fanXpert2 to lower them to the their lowest possible and end up with a very quiet setup. With this in mind, i would chose
Noctua NH-U14S, the cooler was reviewed by
SPCR Noctua NH-U14S Slim 140mm Tower Cooler, and got the editors choice, and for the back fan i would use
Noctua NF-A14 PWM, the fans are very similar, what really changes is the frame, but each will work on their spot, the rpm range and % pwm operation is identical, so controlling them both with the same PWM fan header (CPU_FAN) should net the same rpms under the same % pwm, all will be handled by FanXpert2, the fan comes with the Y splitter already included on the box, so no need to buy anything extra. And for the frontal fans, you can keep the included if you wish, and just use a Y fan splitter, like
Silverstone Tek Sleeved PWM Fan Splitter Cable (CPF01), both fans are identical so fanXpert2 should control them both equally, same rpms same voltage on a given load, etc.
If you were to chose what i suggested, then install fanXpert2 and let it control the fans, run the fan tunning option and it will test the fan, stablish the minimums, and set it up, this you can change to your liking if you want more rpms on a given temperature. I leave you a couple of fanXpert2 of the fans you will have so you can decide what you want to do,
I dont see any mechanical hdds on your build, if you dont plan on using any, then install the ssd on the front of the case, check
[Official] Fractal Design Node 304 Owners Club, for ideas for the build, there are tons of builds there, with different cooler and where you will also find how the mounted the ssd on the front.
And for a dedicated GPU, if you dont have anything demanding, i would chose
MSI GTX 750 Ti Gaming OC N750TI TF 2GD5/OC, check the following reivew for more info,
TechPowerUp MSI GTX 750 Ti Gaming 2 GB, and it should still be a very quiet and gaming capable build.
Good luck,