**UPDATE**
Just wanted to update that we seem to have turned a very positive corner

Sunday he didn't go at all
Yesterday, Monday he pooped at Mother's Day Out, and he did it on the potty!! Obviously I wasn't there (bummer) but they said that he was holding himself so they said "I think you need to go potty" and he walked right in, sat down and had this ENORMOUS poop. They said they were shocked that someone so small could produce so much poop. There was no drama AT ALL!!
Today, Tuesday we went to the park to play and he pooped in his pull-up. Again there was absolutely NO DRAMA. We were eating lunch and he said he needed to go poopers on the potty, which in the past has meant "I don't like this current situation, I want to escape and go play with the sink" I asked if he had to go (b/c he'd *just* peed on the potty) and he said No. 3 Minutes later he was playing on the playground and called out "Mama, I went Poopers!"
We've found that he needs 2tsp mineral oil and a child's dose of FiberMate each morning with his breakfast. DH forgot on Sunday and that was the day he didn't poop. Both are pretty tasteless and blend into food well. DS is loving his breakfast smoothies so that's how we get both in at the same time. Other options have been in Peanut Butter sandwich, applesauce, orange juice, oatmeal, yogurt, etc. His poops have been soft, well formed, and totally "normal" looking...not too loose, not to dry.
The unexpected downside has been that my very pee-trained guy has been having daily accidents. I'm guessing that the poop advancement has caused a little pee regression but I honestly don't care. I'll take this situation ANY DAY over the past 3 months of misery.
I also think our new "poop is normal" attitude has helped ALOT. We don't talk about poop or going on the potty all the time. But when either DH or I has to go, we'll hold ourselves similar to how DS holds himself and say "Oh, my bottom hurts" (DS's phrase of choice) "I'd better go let the poopers out so my bottom will feel better and be happy" then we go into the bathroom and go. Sometimes DS comes along, sometimes he doesn't. We also took the book "It hurts to poop" and modified it to work with our situation. basically we just use the pictures to help tell the story and give it the ending we prefer.
I hope this thread helps out the next mama who comes along with the same situation.