How do I add existing Lists/Categories from iCal/Calendar to Mac OS Reminders?

I am running Mac OS X 10.10.1 Yosemite, with personal data migrated from Mac OS X 10.6 and 10.5. I had hundreds of what 10.6's iCal application called "To-Do" items, in various "categories".

The Reminders application in Yosemite has what it calls "Lists". The left sidebar has entries:

  Scheduled
On My Mac
  Personal
  Business
  Unfiled
  Untitled t

These entries appear related to the sidebar entries in the Yosemite Calendar application. There is "On My Mac", followed by a long list of entries that include the above four:

On My Mac
  Personal
  Business
  Unfiled
  Untitled t
  Calendar Secondary
    Spouse
    Entertainment
  To-Do current
    Work t
    Phone t
  To-Do waiting
    Tickler t
    Waiting for t

The entries in Calendar are exactly the category hierarchy I used in Mac OS X 10.6's iCal application, which of course handled both events (now Calendar's job) and to-dos (now Reminder's job).

All my hundreds of to-do items are in the categories suffixed with " t" (for task). Only one of these categories ("Lists") shows up in Reminders. However, if I click on the entry "Scheduled" in the Reminders sidebar, I see all my to-do items, with their category names (like "Tickler t").

So, Reminders in Yosemite can see my to-do items migrated forward from 10.6 iCal, but doesn't display the categories ("Lists") themselves.

I am not using iCloud, and I don't want to use iCloud. I am syncing with an Android phone, through a non-Apple solution, and there is no iPhone connected.

How can I make my existing categories ("Lists") display in the sidebar of the Reminders application? How can I make the categories ("Lists") which are for events, rather than to-do items, not appear in the Reminders sidebar? Is there a plist or settings dialog which I can manipulate to control the contents of this sidebar?