Great questions, @Phil.
For recurring tasks, it will only show the current instance so that one recurring task doesn’t completely fill up your task list. If you do want to see more than one instance out on the calendar, I would recommend setting 4 different recurring tasks that each recur 4 weeks after completion. That way, you can see the dates set out for the next month and will have the next occurrences build out from there.
Regarding subtasks on the calendar, you can do this using an Advanced Search by searching for tasks in the project and then under “Add Filter” > More > Subtasks : Select “Any”.
Once you run the search, you can toggle to the calendar view of the search.