My 3 y/o has become very resistant to change

I have a 3 y/o son and I just gave birth to my second child two months ago. My toddler is still sleeping in a crib but he is ready to be in a bed. We set up a “big boy” room for my toddler to get him out of the nursery but he refuses to even sit on the bed. He’s also still in diapers and refuses to sit on the potty. He’s still using a pacifier to sleep as well. These are all things I’ve been working on with him but every time I suggest anything about the potty or his new bed he freaks out. Same thing with his binkies. He only has a couple left and if he loses them I will sometimes suggest that he just sleep with out it and we will look later. He screams and freaks out until I end up looking for it and giving it to him. I know I have enabled this behavior to an extent because I didn’t want to push change on him too hard with the new baby coming. It’s also hard to be consistent and firm when I also have to look after the baby now too. His pediatrician also warned me not to push too hard because he may not adjust well when the baby arrives. He loves the baby so much. Always wants to help me, give him kisses, asks where he is if he doesn’t see him. To the best of my knowledge he doesn’t have a problem with the baby. Our routine hasn’t changed much since the baby arrived either. I have offered incentives for everything. Candy/McDonald’s/something else he wants in return for using the potty. I have offered to sleep in his new room with him, I’ve set up all his favorite stuffies on his bed, brought in his binkies, set up his galaxy light in the new room, nothing works. He just shuts down at the mere mention of using the potty/sleeping in his new room. We don’t give in to him 95 percent of the time but we have been giving in to his yelling when it comes to these things. I know that hasn’t set the best foundation for success at this point and I know that. I just need help figuring out where to go from here. Any advice would help.