After potty training three kiddos I can tell you this...no matter how young I started, what method I tried, they were all "potty trained" at 3 yrs old and had no more accidents at 3 1/2. Make it fun...praise success...discipline only causes power struggles.
I do have a "trick" for getting them to poop on the toilet. My sisters and I have gotten 7 kids total trained this way. We bought "poopy prizes". For my son it was Matchbox cars. I bought 7 of them and put them on top of the fridge. Every day he pooped in the potty - he got a prize off the top of the fridge. After one week - never had a poop accident again. Worked w/ my girls and all my nieces and nephews too. Just pick a prize that motivates them.
Good luck!
I do have a "trick" for getting them to poop on the toilet. My sisters and I have gotten 7 kids total trained this way. We bought "poopy prizes". For my son it was Matchbox cars. I bought 7 of them and put them on top of the fridge. Every day he pooped in the potty - he got a prize off the top of the fridge. After one week - never had a poop accident again. Worked w/ my girls and all my nieces and nephews too. Just pick a prize that motivates them.
Good luck!

Take heart that training will happen eventually(hopefully soon) and until then here's a big hug!