1. NO! Alby Hub can and is meant to run behind a firewall or in a private network. NWC (through the relay subscriptions) allows communication with the world
  2. right now you still need an Alby account during the setup. It is used for notifications, LSP recommendations, etc. This requirement will be changed in one of the next versions. It's so far the default during this early release.
  3. Yes. You do this through an so called "isolated connection" - basically a sub account with its own balance. The version which is about to be released contains a "Family&Friends" option in the Alby Hub. It is a full NWC connection and works with any app that does NWC. There is also the Jim app (https://github.com/getAlby/jim) by @rolznz (Nodana even offers one-click deployments of that: https://nodana.io/)
  4. On mobile it is about paying on the Go. You want to send/receive. Alby is about to launch a simple NWC backed mobile app for exactly that. But you can also use an Alby account and then use Zeus or BlueWallet with it. (Signup to an Alby account, configure the NWC wallet and then use Zeus/BlueWallet)