I was just posting about this in another thread, but Tom's Hardware did a roundup of various mid-range graphics cards, comparing performance in Final Fantasy XV...
http://www.tomshardware.com/reviews/final-fantasy-xv-performance-analysis,5513.html
1080p results at medium and high settings are on page 4. It looks like a 1050 Ti would get 30+fps at medium to high settings (assuming their run is fairly representative of much of the game).
They used a 6-core, 12-thread Ryzen 1600X for the tests, but also performed some tests where they disabled some cores to estimate how processors with lower thread counts would perform, which can be found on page 6. Going from a 6-core processor to a 4-core one appears to affect minimum frame rates a bit, but the averages should remain about the same, so long as the per-core performance is similar. As has been said though, you'll want to overclock the Ryzen 1200 on a B350 or higher chipset motherboard to get the most out of its performance.