Hi Hillary!
Thanks again for the advice! I never thought I'd be talking so much about poopy pullups at this point in time!
I say he doesn't have accidents because he never does until he is in bed and he was always wearing a pullup when they happened (till this week). He has long known that pullups will hold pee/poop and has often peed in them while awake, usually in the morning before he takes it off as he would tell me he didn't need to use the potty cause he went in the pullup.

My daughter always did that too though so I never cared that much about it.
We have also never made a big deal about wet pullups as my daughter has a kidney disorder and will likely be in a pullup for awhile. So because she clearly has no control over her situation, we would never say anything to either kid about accidents. We also never really say anything to him about the poopy pullups at the time because he's generally asleep by the time we know anything happened. The next day we've always asked about it, but only to say that he needs to try to get to the potty on time or call us if he needs help. We remind him of this before bed as well.
Neither kid has ever seen me sick from this pregnancy and until last week they had no idea as we never mentioned it or anything about it. With my son, I was very sick then too and the one time my daughter saw me throw up she was horrified so I made it a point to never let that happen again. Not that they still couldn't have sensed something, but my adult BIL and his GF were with us a week and didn't notice a thing, so I'm guessing my kids didn't either. Henry's also in camp everyday like his sister so he shouldn't have any resentment there. There was nothing specific in his life that changed around the time this started. Prior to this starting he never pooped after he went to bed, so it's not like he was previously leaving his bed to use the toilet and then stopped, it just seems his potty schedule has shifted later.
I know all potty issues, when a child is ready and trained anyway, are control issues of sorts, but we've been pretty laid back which is why I had no idea which way to go with it. He's never been punished or yelled at about it. The most we've done was this week when we told him no pullups (which he loves cause they have Diego on them) because he's wasting them.
Teachallday - Have you actually put a child back in diapers day and night like that? How do you know the kid won't decide they like the convenience of the diaper and just use it and scrap the potty altogether?

It seems a little risky that he might just capitalize on the ease of going wherever he is and letting me clean him when it's convenient for him, assuming I could in fact get one on him that is. I don't want to create a bigger issue by mistake.
Last night I did tell him he had to wear a diaper to bed since he was not using the toilet and he refused and opted to go to bed naked. I will keep offering those 2 choices, but I can't exactly force him to wear the diaper as he can remove it himself. That is how he told us he was ready to train a year ago, he just took off the diaper as soon as we got it on him, every time. So while I could fight him to get it on, I know he'd take it off if it's not what he wants to wear. I don't see how I could get him to keep it on by telling him only grown-ups can take it off.
FWIW, when he chose to sleep without pants (as I said the diaper was a requirement for pants as I did not want to clean poopy pants) he did poop in the toilet before bed and did not go in his bed.
We will make a sticker chart today and tell him he gets a sticker for every night he uses the toilet instead of his pants/pullup/whatever he has on. We'll also be telling him the vacuum is dependent on staying clean, which should hopefully have an effect as he loves that thing. And again offering him a diaper at bedtime.