supplementscene: I was thinking about going for a more the powerful Ryzen 1600 and GTX 680 combo (or something similar on the second hand market). Do you think this would be a significant improvement or slight improvement over your suggested system? What PSU would handle that system?
That would be a lot better (the 1600 comes with a better cooler too). Either of the suggested PSUs should be sufficient.
I'd normally agree with ariaspi about trying to get a PSU made by SeaSonic or SuperFlower, however those come at a substantially higher cost. Other PSUs may not be as good, but they should be ok as long as you stick to trustworthy brands that have a lot to lose if they put out garbage.
Still, here's one that likely uses a SuperFlower design according to the site ariaspi linked to:
EVGA 650w B3 PSU 80+ Bronze Fully Modular Power Supply £69.99:
https://www.ebuyer.com/791242-evga-650w-b3-psu-80-bronze-fully-modular-power-supply-220-b3-0650-v3 supplementscene: Would Linux live with the drivers for my suggested CPU/GPU?
It'll be fine - I use a Ryzen system myself (R7 1700 with a light overclock to 3.7GHz). I'm currently using an AMD graphics card (RX480) but I used to use an Nvidia GPU in my old system. Once Nvidia's proprietary drivers have been installed it should be fine, although prior to that you may need to boot the system in compatibility mode (this is detailed in my Mint guide).
supplementscene: What percentage of my game library Steam/GOG could I get to work in Linux? (obviously that's an unknown but roughly on average).
Obviously anything that officially supports Linux should work, likewise for anything supported by my wrappers, ./play.it, Lutris, and Steam's SteamPlay feature (which allows you to install and play Windows-only games using their custom version of Wine).
For other games, you can try setting them up in Wine manually (front-ends like PlayOnLinux and Lutris are very helpful for this). SteamPlay also allows you to try unsupported games to see if they work, but you'll need to enable it.
supplementscene: I also have a labeling software for my business from 1998/1999 that won't run on 64 bit Windows operating systems (it maybe 16 bit I'm not sure). My dad's been struggling to run it on Linux (it works on Windows 7). It seems Linux can't find the fonts the program uses. Any thoughts on that or any forum I could ask about it?
What exactly happens when you try running it? You could try installing "corefonts" using Winetricks & see if that fixes it.
supplementscene: So a GTX 680 requires a Two 6-pin. I this the: 2x PCIe Connectors (6+2-Pin)?? Will that fit or is it too big? And do I need 1 of those for the Motherboard/CPU? Sorry completely newbie Qs
6+2 pin PCIe connectors can be used as either a 6-pin or 8-pin connector depending on what the graphics card requires. There are separate dedicated power connectors for the motherboard.