You can install Windows inside a virtual machine (VirtualBox, virt-manager, etc.) inside PureOS. That way any spyware that you have running inside Windows should be limited to only accessing what is inside your virtual machine. (If you want this, don’t set up a bridge to access the Linux files inside your Windows virtual machine.)
The problem is that running Windows inside a virtual machine is going to hurt the performance. It is fine for normal stuff, but if you are doing 3D modeling, you are probably going to want all the performance that you can get. You can set up a dual boot machine. If you want that, then don’t buy the Mini with PureBoot, since that doesn’t support Windows. You need to select Coreboot + SeaBIOS when buying.
You can shrink the existing Pureboot installation and install Windows in another partition, but that is complicated for a Linux newbie. Instead, I recommend that you install Windows in the complete disk, which will overwrite PureOS. Then install PureOS. In the PureOS installer, there is an option to shrink the existing Windows partition. Then you will have a Grub menu to select either Windows or PureOS when booting.
You probably won’t have any problem if you are using USB devices. Every USB mouse I have ever tried works in Linux. Often you can find out if your device are compatible with Linux just by Googling the model number of your device and “Linux”.
Bluetooth devices are a problem because the Atheros ath9k WiFi/Bluetooth card in the Mini requires that you install proprietary firmware for Bluetooth. Because ath9k cards have poor performance, the easiest solution is to install an Intel WiFi/BT miniPCIe card.
If you are really worried about whether your mouse/webcam/keyboard works with Linux, you can download a Live CD of Debian and burn it to a DVD or to a USB memory stick. Then, boot up your current PC in Debian with the Live CD and see if your hardware works.