msremmert

You know if you stated you were using a VPN in your OP that would have been useful. Just for future use while troubleshooting, keep that in mind to list the details! (Even if you don't think they are important details)

Not needed. Stick with stereo.

Have you organised any LAN events in the past? I personally haven't organised one into the double digits for about 10 years now but off the top of my head, have you got the following bases covered?
 
Electrical requirements? If 50 people with decent PCs turned up, the electrical requirements will probably require thought.
Assuming it were over more than 1 day, sleeping arrangements?
Food?
Tables/Chairs?
Network configuration?
Games to be played?
Dedicated game servers?
File shares or places to download game patches? (Legal or illegal, people are gonna share files...)
Internet connection? Assuming the games are on Steam, is there enough bandwidth to allow 50 people to download any game updates that might catch them or you off guard?
Entrance fees? Fun swag and giveaways? Events that size might net you corporate sponsorship.

If it's an older model (no HEVC support), then it will not do it in 4K. The newer ones should do it. 
 
You'd want Kaby Lake for Netflix 4k, unless you're running an Nvidia Geforce 10xx GPU with 3GB dedicated memory or higher.

My home network