Well, those, and:
1. Speed. It took days for heroku customers to be told about this.
2. Customers sign up at "heroku.com", the platform is called "Heroku", the CLI is "heroku", everything's heroku, so don't send emails from a parent company (Salesforce), send them from "Heroku".
3. Unambiguous info on what customers need to do. I had to guess based on HN comments whether config vars were accessed. Config vars are 100x more sensitive than code. Comms should be unambiguous and complete, and if incomplete for any reason, explain that (e.g. we don't know yet).
4. I still don't know whether having 1 Github Deploy on my Heroku account allowed unauthorized access to all heroku applications on my heroku account (i.e. those using other deploy methods, like `git push heroku main`). Were all my apps' repositories able to be accessed, or just the one(s) deployed via Github Deploys?
5. I still don't know whether unauthorized access was gained to all other GitHub respositories on my GitHub account, i.e. the repos that aren't heroku apps.
These said, I still really appreciate that security incidents happen and aren't easy to deal with, and there's no obligation for anyone at a profitable company to actually care about semi-captive customers, so thanks to Heroku for the efforts; it's genuinely appreciated.