I'm not with Laminar Research, just a fellow flight simmer in the UK and as far as your Question 1 is concerned, I'm sure that a GTX1050Ti graphics card would be more than acceptable. In fact I have seen PC spec's on this Q&A where simmers are using GTX670's, in fact I did until recently and I had no issues with it at all, albeit I was only using two 1080 monitors.
As far as Question 2 is concerned, a couple of comments:-
1. You could always add more RAM, but there would be little noticeable improvement
2. If you're going to update your graphics card, then you may have to think about upgrading your PSU, as some graphics cards can be quite power hungry. For example according to Nvidia, the minimum system power requirement for a GTX670 or GTX1070, is 500W. This already exceeds your total PSU capacity.
3. Your 2no SSD drives at 256GB each, assuming these are two separate volumes and not set up for RAID in anyway, would be too small, as the whole of the X-Plane 11 file structure is over 256GB on its own, well mine certainly is.
Lastly the Windows OS and CPU look fine.
Hope this helps :-)