Fastmail is really well set up to be a family account provider. You can add multiple domains, aliases to various accounts, and you can mix and match account levels now (kids accounts can be cheaper ones than your own, but still share your domain). Their spam filter works better than Google or Microsoft's, and I set up aliases that deliver to say, my wife and I, so we can both be notified of updates for particular accounts and such.

If you have any issues, a real person will answer your support ticket.