Clean up all TODOs and review code smells

[beechnut]

During the migration, we've left TODOs, comments, notes about code smells, and notes in the commit history.

As we get ready to release the new site, we should clean up and review all of these.

### Search codebase and commit history, and review all:
- [x] `TODO`
- [x] `TO DO`
- [x] `code smell`
- [x] `Note`
- [x] `should`
- [x] `still`

[beechnut]

All of the TODOs, code smells, and notes are reasonable and can be lived with. There's nothing urgent that has to change prior to release.