Congrats on the new addition!
My 3 y/o is now going through her pooping protest phase as well.
First off if you can, get out of those diapers all together! Mine needed to feel what she was producing. I know it's hard, but they became a crutch for her to continue to release herself in them. If you can go strictly cotton, do so, but in combination w/ the vinyl trainers thats good to start off with.
No laxatives! Pear juice works wonders! Apple juice too, but within 30-45 minutes, he will naturally have to go. If he's crying/kicking to push it out, the pear juice goes through the system that the kicking will make the poop come down faster. Still time & take him every 15 to 30 min after consuming the juice to get him ready.
Occasionally, after getting a feel for his usual time to pee and poop, try allowing him to run around in the buff. If there are other children around, use your judgement. His facial expressions and body language will give you cues that he's ready to do something - then begin taking him to the potty. Yes, there may be a few accidents, so a non-carpeted area is ideal.
Sidebar: I also tell my potty princess as I call her, that the poop is screaming to get out and the only way you can hear it is if she pushes it out. When it's close to that time, or she disappear to go in a corner/secluded place to release herself, or after a little poop is visible from her bottom, we race to the potty, sit her down then chant "LET ME OUT, LET ME OUT" together. After it falls in the toilet, we both do a quiet scream (as if the poop was doing it) then cheer, clap & say "Yea". Every now and then, she's now tells me when she has to go that "The boo boo is screaming to get out, mommy"