So I finally decided to replace the LXD that comes with Ubuntu 18.04 with the Snap version of LXD because the default .deb version of lxd would hang when I ran lxd init or when I ran any lxc command such as lxc init. This system, this would be LXD host, is a KVM guest.
Then I created an Ubuntu 18.04 container with lxc on the KVM guest which was now running the Snap version of LXD and I found that lxd and lxc commands such as lxd init or lxc launch ubuntu:18.04 test would work just fine. There was no hanging whatsoever. And this was running the stock .deb version of LXD inside of an Ubuntu 18.04 container running inside a KVM LXD host.
I really don't like this Snap system, especially since it doesn't seem to offer users much control over updates and that could cause services to fail.
What I think I'll try next is purging the LXD related packages from a fresh install of Ubuntu 18.04 on the KVM host and then reinstalling those packages. Maybe something will be different. Maybe the KVM image the host is using is broken in some way. I hope not. But that's what I"m going to try next.