Daniel,
I don’t think you need any microflows to build the page you want.
I created the following domain model which is the same as your domain model, I think:
Next, I created a page that has a parent DataView for entity WorkoutTracker, a nested DataView for entity ActivityInventory (via association WorkoutTracker_ActivityInventory) and a ListView nested inside of that to display ActivityImages (via association ActivityImages_ActivityInventory).
Is this what you are trying to build?
Mike
**EDIT**
another way you could accomplish this