Hey, kind of!
You can generate and use multiple Nostr keys in the Extension. They work entirely on your machine and are a separate thing from Alby Account, LNURL and NWC.
Yes, you can have multiple Alby Accounts,registered on different e-mails (you need an invite code for new one, though). If you launch Alby Hub, you will get 'invite a friend' feature in your Account, so you could invite yourself. With each Alby Accounts comes one LN Address.
Moreover, in the Alby Hub you can create Isolated NWC Connection, that effectively creates subwallets on your Hub node. Then you can link Alby Accounts with these NWCs, so few LN Addresses could share one node (but with separate balances).
Hope that helps!?
Oh wow, thank you. I will try all of this and report back.