A.B.
This is a control issue. He knows what to do and when, and he is refusing.
The pull-up is enabling him. I know the prospect is daunting, but I would go cold turkey off of them. No going back. Throw them away and let him help you. "I'm sorry, buddy, but you're a big boy now and big boys wear big boy underpants. You can do it!" If there is a mess, he can help you clean it up and see how yucky it is.
Many articles / books I read said that once he is going regularly during the day and staying dry during naps, it's time to take away diapers at night. Once our son was going, he wasn't interested in wearing his diapers anymore. I was so tempted to get pull-ups "just in case", but I went with the "no training wheels" route and I'm glad. I was truly dreading cleaning up messes and it happened one time, that's it. DS helped us clean up and now he has that association - if I don't go to the potty right away, there will be a mess. Yuck!
It takes courage, but you can do it! Good luck!
ETA: We do potty two times at night. No drinks after dinner, potty before bath, Pjs, stories, potty again, then bed. He usually ends up peeing both times and he's been dry through the night, then up around 6:30 to go.