“Areas of focus” would be a high-level checklist of all the areas in life and work that you want to keep your eye on, ensuring that you are doing what you need to be doing to maintain them at your standards. Examples might be health, relationships, career, finances, creative expression, etc. You may or may not have actions and projects about them—if the area is fine and “on cruise control,” no need. But if it’s not where it needs to be, you need to ensure that you have projects and actions to get them there, such as “Set up regular exercise program,” “Call Jim re: suggestions about health clubs.”
“Someday Maybe’s” are things that you might want to do (about anything) at some point, but not yet. You just want to be reminded about them on some regular basis to ensure that you are OK with the fact that you’re not doing it yet.
For example, learn Italian, climb Mt. Everest, own a vineyard. You will probably have “Someday Maybe’s” in many of your areas of focus as well as active projects.