Yes both will fit, and both are powerful enough. However, you will have to get something like this if you use an SFX PSU in an ATX case: http://www.corsair.com/en-us/sfx-to-atx-psu-adapter-bracket
SF450: 12.5 x 10 x 6.3 cm
VS450: 15 x 14 x 8.6 cm
It is good but there are a few improvements that can be made:
1. AMD's latest BIOS update made it so ryzen CPUs can handle up to 3200Mhz RAM. you don't have to get it that fast, but consider getting something a little faster.
2. You will need some case fans
Hyper 212 evo is a decent option.
If you want a more beefy option for a better OC, then I would recommend a cryorig H7.
However, if you want the best of the best, get the cryorig R1 uneversal
You will need to get more VRAM, but it looks pretty decent.
I suggest a 1050ti
BF1 might be a little problematic because it is a very CPU intensive game
P.S. I hope you are planning an upgrade sometime soon.
Looks pretty good. if you can afford an SSD, then get one. if not, then get a hybrid SSHD instead of your HDD
2.5 inch one:
http://pcpartpicker.com/product/w6x9TW/seagate-firecuda-1tb-25-5400rpm-hybrid-internal-hard-drive-st1000lx015
or this 3.5 inch one...