Questions about setting up a production version

I've started playing with setting up a "production" version of PieFed. I have a few questions. I'm hoping someone can help.

1. Can I use S3 buckets for media? I use Wasabi S3 for my other Fediverse servers. Can I use them with PieFed?

2. Regarding the BOUNCE_ADDRESS settings in the .env file, what if I leave them all unfilled? Will the email bounces simply come back to the inbox of the sending email address? This is my preferred scenario.

3. The instructions have, "If BOUNCE_* is configured ...". Where is it configured? If I don't provide bounce addresses, do I need to care about this configuration?

4. For production, do I change MODE to MODE='production', or something else? Is it case-sensitive?

5. What is the SENTRY_DSN variable?

6. What happens if I set MAIL_ERRORS=True?

Thanks, much! I'm sure I'll have more questions.