Can I use xvfb with AWS Lambda?
No, this breaks the lambda paradigm of having a fully built container ready to go.
Also, anything you'd do with xvfb is probably going to be slow.  As a general rule lambdas should execute in under a second, otherwise you should just have a server.
I would recommend creating a docker container and making an auto-scaling group.
I would like to offload some code to AWS Lambda that grabs a part of a screenshot of a URL and stores that in S3.  It uses chromium-browser which in turn needs to run in xvfb on Ubuntu.  I believe I can just download the Linux 64-bit version of chromium-browser and zip that up with my app.  I'm not sure if I can do that with xvfb.  Currently I use apt-get install xvfb, but I don't think you can do this in AWS Lambda?
Is there any way to use or install xvfb on AWS Lambda?