I don't understand the problem with the berries for dessert. As I recall RCI has desserts which use various berries, so simply putting a plate of them together shouldn't have been a problem. Avocado? Could be just something they don't stock up on for Alaskan cruises. Just guessing. But since you got it one night we know they did have at least one!
When we went to Alaska on a 7-night with RCI last summer, we had zero lectures or naturalists aboard.
I've run the gamut on beef and lamb with RCI - sometimes great, usually average, sometimes mediocre. Great lamb shank on the Sovereign last summer, not-so-good on the Rhapsody two months prior to that. Could be a supplier issue.