the 2gb and 4gb performance different won't be too much, except if you're playing texture heavy games like modded skyrim, bigger RAM would be a huge advantage and less crash. but of course, 1050TI are expected to work better than the normal 1050, so i suggest u get the 1050 TI instead, just like me 😀
for the RX 460 i would suggest u buy gtx 1050ti instead, the RX 460 4gb price are too close with the GTX 1050 TI so it's not worth it
h110 will need a bios update if u want pair it with 7th gen intel, get either b250, h270, or z270 instead if u want less work
for RAM: unless u're planning on buying another 8 gb later on i suggest u get 2x4 instead