Windows 7 also runs on a Ryzen. See the article from Computerbase:
1. www.computerbase.de/2017-03/ryzen-installation-windows-7-am4-anleitung/
2. https://www.computerbase.de/2017-03/windows-7-8-update-kaby-lake-ryzen-update-3/
According to the manufacturer's no.: YD170XBCAEWOF, this should be the version without a fan (WOF = Without Fan).
Even though the description from Digitec says with a fan.
I also meant that I read/heard somewhere that the first available models will be without a fan.
It depends on the processor. This one doesn't have its own graphics unit, so you'll actually need a dedicated GPU. The CPUs with an integrated graphics unit end with "G". However, there are no high-end models with a graphics unit.
E.g. this one: AMD RYZEN 5 2400G (AM4, 3.60GHz, Unlocked)
If you don't need graphics at all (headless system), it depends more on the mainboard. Many BIOS systems wait for a keyboard and a graphics card when booting. You won't need either with a headless server. Therefore, it is much more important to find a mainboard that can be safely booted without these two components.
Depending on the operating system, you will need a GPU at least to install the operating system. Alternatively, you can install Linux without a GPU, unsupervised via PXE, but you have to configure this in the BIOS... for this you need a GPU.