When you send out an unencrypted, digitally signed message or a message with your public key attached (so you can send encrypted messages to them in the future), can't that message be intercepted and then the "hacker" would then have access to read any of your future encrypted emails they intercepted in the future?
When you send an encrypted email, if the recipient replies without actively selecting options to encrypt their reply, is your previously encrypted content in the body of the message now sent back to you over the Internet in clear text?
If you send an encrypted message to someone and the recipient has an Outlook rule that forwards messages to another account (gmail etc.), is the message still protected with encryption when their Outlook rule forwards the message?