Best route to archive character looking in someones eyes irl

Hello! Ok so this is not an easy task and I don’t know how to go about it.
A bit about the project I’m trying to develop. So we are launching a brand new gaming bar in Norway where people can come in and rent a computer, join tournaments or just take a beer and watch some E-sports. I’m in charge of the design and development of this bar, and after watching CodeMiko I got extremely excited to implement screens throughout the bar that show a virtual world with people chilling, walking, working, etc normal stuff. The board loved this idea and I’m now in charge of creating and implementing it. That will be hard, but that’s not the hardest part.
The idea is to put a vertical screen at the front door of the E-sports bar with a virtual environment. When a person comes to the door a character will walk in frame, stand up etc and look the person in the eyes and say a random greeting.
Ok, so I have never used Unreal Engine(if you don’t count the 2hours I played with it), but I have worked professionally with blender and C4D and I have programmer experience with eye-tracking and can calculate the height, the direction of look, etc.
My question is how do I pull it all together and in which order. I know I can create a 3D environment with a character that semy randomly does actions, but I have no idea on how to connect that to my eye tracker program. This will also have to play in real-time so when the person walks up to the door, the character looks them in the eyes. I have a camera and sensors and a powerful PC to run it all on, but I don’t know how to connect the pieces with an IRL camera, eye-tracker code, and character interaction in Unreal Engine.
Any suggestions on what to do or in what way to proceed?