Newb NK 4.0 build

Ok total newb here. I found this site a few days ago doing research on this project. First off Amazing!!!

My current set up is a 5tb external hd hooked up to an android box. I rip movies on my desktop, transfer them to the external, then hook it up the android box. I use Kodi for playing media. For the most part I’ve been happy with this set up but the HD is beginning to get full and I’m worried about it failing as it is a bit long in the tooth.

Reading over the NK thread here is what I’m thinking of getting
Motherboard - Acer Q77h2AM
Ram - PC3-12800E 16gb
CPU - i7-3770
CPU Cooler - Arctic Freezer 12
SSD - Pioneer 512gb
Power Supply - Be quiet! power u9 500w
Case - Fractal Design Node 804

I’ll be getting 3 8tb elements and shucking them.

1st question. Does this build seem like a good one? Would I need anything else or different you would suggest? Basically I want to run a plex server on it. Stream to my home android box and maybe to my iPhone when I’m out and about. Personally I’d like to keep Kodi on my android box. I just like the interface more than plex. So maybe run a wire from the server to the box and point Kodi there. I could run the Plex server at the same time, right? and just Plex server for streaming to mobile devices?

2nd question. Roughly how may streams could I expect from a setup like this? My initial need is just to serve my home setup but if for this or a few dollars more I could hook up some family and friends that would be really cool.

Any info and help would be appreciated. I’ll post pics as I build it.