16GB Ram is pretty standard nowadays anyways if your going to be playing games and streaming. As far as the SSD, they're dirty cheap nowadays. SSD for your OS and some games makes everything smoother and faster. As for the CPU, whats the budget?
https://www.newegg.ca/Product/Product.aspx?Item=9SIAG0H7RV3780&ignorebbr=1&source=region&nm_mc=KNC-GoogleAdwordsCAMKPL-PC&cm_mmc=KNC-GoogleAdwordsCAMKPL-PC-_-pla-battlegroundsca-_-Accessories+-+General-_-9SIAG0H7RV3780&gclid=CjwKCAiAqt7jBRAcEiwAof2uK0Jxx5J2M9_vc2tMupELpSRMnEUWzkSHoectPjiIyvMhudIydX7vtBoCQkMQAvD_BwE
Not looking to get this GPU, just came across it while browsing.
Just work out the better deal for the GB. What are you using your PC for? Speed doesn't matter if you're just gaming. Some ram is actually overclockable in the BIOS.
I think the i5 route isn't bad at all. The i7 probably isn't needed for gaming anyways. Paired with the RX580 should be more than enough for 1080p. No need for the Ryzen and mobo as the 3470/3570 is backwards compatible with the mobo you have right now.