Kind of, in that you can use it to replace Tailscale if you want. Using Yggdrasil as a DIY Tailscale replacement is probably less work than manually configuring WireGuard, because it handles the mesh features of Tailscale for you.
All nodes are publicly routable rather than private, though. If you want to lock everything down to emulate Tailscale, you can just configure your firewall to only allow traffic from a whitelist of your devices' Yggdrasil addresses[1].
I don't really understand what you mean. Yggdrasil will automatically discover and peer with other hosts running Yggdrasil on your network. Connecting your network, across the internet to another network is no different than connecting to a public peer.
My biggest concern with Yggdrasil is that, without careful configuration of every node, anyone can connect to your Yggdrasil network and potentially expose it to the public Yggdrasil network.
I've moved on to experimenting with Nebula (made by Slack). This is made specifically for closed networks and has built in tools to restrict access. I still REALLY like Yggdrasil and will continue to experiment with it; just not for private meshing.
Kind of, in that you can use it to replace Tailscale if you want. Using Yggdrasil as a DIY Tailscale replacement is probably less work than manually configuring WireGuard, because it handles the mesh features of Tailscale for you.
All nodes are publicly routable rather than private, though. If you want to lock everything down to emulate Tailscale, you can just configure your firewall to only allow traffic from a whitelist of your devices' Yggdrasil addresses[1].
[1]: https://yggdrasil-network.github.io/2018/07/15/remote-access...