Thanks MaxGuru, but that absolutely did NOT do it. That was one of the first things I tried.
OK -- so, I have returend from a TWO HOUR Genius Bar appointment and here is what we figured out: there was NOTHING that could be fixed to prevent the duplicates, not matter which solutions we tired (all those mentioned in the forum, and elsewhere).
What did we do?....First, I have always backed everything up, so I had backups to play with. Make sure you back up everything before you try anything else I mention here (i.e. do an export for iCal, Address Book etc. -- I worked from fresh copies from my Time machine backup from Monday before all this mess started to assure it was as clean as possible.) I put those on my desktop for the time being so we can access them quickly and easily.
Step 1: delete all calendars, address book, reminders, notes from desktop, iPhone, iPad, and iCloud.com (yes, delete it all).
Step 2: put a clean copy of all that data back on your Mac (or PC) from your backup.
Step 3: In iCloud, turn off all calendars that they create that you are not using (work, home, calendar for example are calendars iCloud creates that I have never used since I have created my own and named them MyLastName, Holidays, etc).
Step 3: Turn iCloud off everywhere: on your iPHone, on your Mac, and on your iPad. Make sure you turn off every single feature, not just calendar. Totally turn everything off. LOG OUT OF ICLOUD.COM, DELETE iCloud account on your iPad, DELETE Icloud account on your iPhone.
Step 4: Restore your calendar, notes, address book on your Mac from backup (do not restore reminders - those are gone, never use old ones again, you'll create new down the road -- it just will not sync no matter what from an old copy at this point)
Step 4: Hard-wire sync your iPad and your Mac through iTunes. You'll have to turn on all the sync features. DO NOT sync your iPhone (unless it will be the only thing you sync with your iCloud and mac). Go back into the Info tab and after syncing turn off all the sync features you turned on (contacts, calendars, etc)
Step 5: Disconnect from iTunes
Step 6. Log back into iCloud.com on your Mac. Leave it be.
Step 6B - and this is important: On both your iPad and your iPhone, turn off all calendars that are not yours as per above.
Step 7. Log back into iCLoud on your iPad. Your iPAD will become your primary sync source. Now go ahead and one at a time turn on the address book (wait a bit, check icloud.com on your Mac to make sure it was connected properly). Then turn on the calendar (wait a bit -- depending on how big your calendar is, it might take 5-10 minutes for it to all upload to iCloud from the iPad). Check iCloud to make sure it is there. Same thing with all the other features -- one at a time from the iPad first.
Step 7. From your Mac, go to Preferences>iCloud> and turn on one feature at a time. It should now be okay without any duplicates being introduced. Give it a few minutes to make sure everything remains stable.
Step 8. Now connect your iPhone to iCloud-- be aware this might cause duplicates on your iPhone -- not to worry, there is a way to fix that. Add one feature at a time as you recreate your iCloud account on your iPhone. Start with Address, then then others...
Step 9. Check your iPhone calendar. You might have duplicates on your iPhone. That is okay. DO NOT do any further sync at this time. If you only have one copy of your calendars on your iPhone, you are good to go, and your iCloud connection should now be stable. Step 9B -- If you have duplicates on the iPhone, go to iCloud settings on your iPhone, and uncheck Calendars. When it says delete all on this iPhone, select yes. Wait a moment. Turn your iPhone back on. It should within a few moments push one single copy of the calendar to your iPhone. Now your are good to go.
Why this is such a hassle, is anybody's guess. We literally had two Geniuses at my local Apple Store working on this with me, and we had Apple's Tech Support on the phone the entire time through the process. When it takes about 7 people to correct a simple iCloud tech problem, you know there is something seriously amiss and there will be a lot of problems with people using iCloud for the smartphone features rather than the entertainment features down the road.
Anyway -- hopefull this might work for some of you. If not, good luck in finding your solution.
The overall answer seemed to have been to a) completely delete all old data and backup clean copies, and b) use the iPad DEVICE as your primary inital iCloud sync source. How backward is that, when your desktop/laptop should always be one's primary source.