Kermit, so fancy! I remember the excitement of discovering ZMODEM and how much better it was than the old standard of XMODEM.

Each alias has a configured delivery destination. Aliases that only point externally never reach the main account inbox.

You are limited to replying from the gmail unless you jump through more advanced hoops. Those include telling gmail in its settings that it can “Send mail as” something else, and also giving gmail authorization to send mail for your domain by adding them into your SPF and DKIM records. Those are more complicated than I want to describe here, and it will be complicated to merge both mailbox.org and gmail into them, so if you don’t already know about them, let’s just say yes, you can only reply as the gmail user.

I don’t know about mailbox.org, but with Fastmail I use a combination of explicit aliases and a catchall alias. The catchall and some individuals direct to me, but other individuals go to me and my spouse@gmail, while others go only to spouse@gmail. The per-user fee is about how many distinct mailboxes with different passwords exist in the service, so I’m only paying for one for me, and the aliases are configurable to resend incoming mail externally.

I’ve been thinking for a little while that it might be interesting to build on a pair of glasses with a couple IR LEDs at either edge and a battery pack to light them up. I can’t decide if that would be good to wear to a protest because the glare would likely obscure your entire face to cameras, or if it would be a bad idea because you’d stick out immediately on any surveillance.