T.Q.
Hi There,
As far as the pulling up his pants issue, if there is no physical reason why he can't do it himself (ie. coordination or fine motor), then you are just going to have to lay down the law. Tell him he pulls them up and down himself, but a grown up can help with buttons/zippers etc. As far as pooping in the potty, it is very common for kids to not poop in the potty for MONTHS after they are pee trained. My daughter was completely pee trained for 5 or 6 months before being poop trained. She too would ask for a pull-up... the one rule we had was that bathrooms were for pooping, so when she had the pull-up on, she had to go in the bathroom. We always told her she could use the potty by herself if she wanted to. What finally worked for us was putting the little potty in her bedroom (she usually would go first thing in the morning when she knew she had the over-nite diaper on). So, I left the potty there, and said that if she had to poop in the morning she could do it herself and call me when she needed help. Sure enough that was what worked... I think they just need to be in control, and do it when they are ready. Just don't push it, and try to find a creative way for him to have the control...
Good Luck!