K.R.
You've tried everything that I would have tried and have tried. Try contacting A Mother's Haven in Encino. They have a sleep consultant who really helped us. My son was a horrible napper unless I was home with him and he didn't sleep through the night. She gave me a few tips that with a little bit of time and consistency on my part really paid off. Now he's taking 2 hour naps twice a day whether I'm home or not and sleeping through the night.If you're not in the LA area I they're website is www.amothers-haven.com. I'm sure you could get help over the phone.