Question about ASUS GeForce GTX 1070 STRIX O8G GAMING

- You do not need the additional thermal paste.

- I would strongly advise you against the enclosure. Because: Overpriced, poor workmanship, no space for cable management.
I would rather recommend the Corsair Carbide 200R (Midi Tower, black). This is also small but much better made.

- You still need a power supply. This one is easily enough for your setup: Cooler Master G450M (450W)

- The CPU cooler is completely overkill. This one is easily enough: be quiet! Shadow Rock Slim (16.10cm)

- RAM is ok. 8 GB would also be enough, but you can leave it as it is.

- Processor is exaggerated. You don't need the "K" variant. I would advise you against overclocking, brings very little anyway. Rather take this one: Intel Core i5 6500 (LGA 1151, 3.20GHz)

- Mainboard is good.

- HDD is good.

- You don't have a drive. It's not absolutely necessary, but they're almost free. So I would take this one, in case you need one anyway: Lite-On iHAS124-04, DVD-Brenner, SATA, Bulk (Black)

- With the money you save on the CPU, the cooler, the thermal paste, possibly the RAM and the case, you can buy an SSD for Windows. This will speed up your PC considerably. Samsung 850 EVO Basic (250GB, 2.5")
You can install Windows and all your programmes on it. You can move your library to your hard drive (if you don't know how, you can find instructions on the internet).

Have fun with your computer!)

A power supply unit would still be appropriate ;) I think 600W-700W would be ok.
I would also use an SSD for the operating system (about 256GB should be enough).
The CPU cooler is an overkill in my opinion, you only have one CPU_Fan connection on the mainboard anyway, I would recommend this one: Alpenföhn Brocken ECO (15cm)
I have already used it in combination with the processor, it cools enough.
Otherwise it should work like this :)