Sounds like you’ve done a bunch of research! Since you’re using unRAID, setting up your services shouldn’t be too difficult.
For your torrents and VPN, there’s a few in the unRAID community store - I’d recommend qBittorrentVPN from Binhex - here’s the documentation for setting up their VPN-enabled containers.
For Headscale, I don’t have any direct experience but unRAID has a decent Wireguard plugin, and should get you up and running in a pinch.
And for your self-hosted services (especially Bitwarden) ensure you’re not exposing this on the net, by VPN is the only option I’d recommend. Even so, I prefer to use Bitwarden’s hosting with a family plan, for peace of mind and resiliency. It’s also much easier for my family.
UnRAID is a great place to start - it allows you to scale cheaply as you need and is easier to fix mistakes. Good luck, and happy homelabbing!
I’ve got this one in my calendar already, and have organised preliminary accommodation!