Of course UEFI comes with its own risks, as we have recently seen, so it is more imperative that you trust your hardware maker when using UEFI. Not that trusting them wasn't always essential, but their toolkits for being naughty have expanded.
NoMachine (NX) is a great option when you have a Linux server to run it on. Does the Linux box have LAN access to the boxes that you want to reach from it?
This is actually surprisingly powerful for what they are doing with it. Quad cores for a little thing like that? I wonder if it ever gets utilized in any serious way.
OpenLDAP is what the average Linux shop is going to turn to when looking to implement an "AD like" authentication mechanism when no Windows is involved.
I had one of these (older model) Of course only had a one year warranty and at 13 months it starting having a problem where it would not power up. sometimes unplugging the battery would do the trick, but that required using a torq driver to remove the bottom.