Need help on upgrading my pc

Hello, I'm pretty new to this sub and pc building, my current pc is a pre built that I'm looking to upgrade, mainly by switching graphics cards, cpu and ram. But here's where things get tricky, my motherboard is a Gigabyte H81M-S1. I was looking into getting an intel core i7-4790 and two hyperX sticks (2x8) DDR3 as PcPartPicket showed to be compatible.

However, I can't seem to be able to find those specific parts to be sold on Brazil, so I was considering going with an core i7-5820k and two DDR4 sticks, funny thing is, PCPP does not show any of those, and all filters are off.

My question is, is it fine to use those as alternatives? Are they compatible?