Are activity notes available in Oracle Sales in the Redwood User Experience?

Yes. Starting with Update 24B, you can enter and view notes on tasks and appointments in Oracle Sales in the Redwood User Experience. There's a separate section for notes on each activity. Interactions don't have a separate notes section. For interactions, you take notes directly in the interaction itself.

Here's a screenshot of a task highlighting the Notes section.

The notes you take in activities don't appear in the list of activities (the activity stream) for the record the note is associated with. For example, if you enter a note for an account appointment, then that note doesn't show up in the list of activities for that account. It's only visible in the appointment itself.