Hi R.. Regarding his objection to telling him what to do, I've offered my son the option of doing the required activities himself and remind him when he's making the choice to wait for me to tell him what to do. Morning routine for example; when he's resistant to getting ready to leave the house I remind him that if he doesn't want me to tell him what to do he can start getting ready by himself. Several reminders and often I'll have to start pushing when time runs out, but always keeping clear the choice he's making. I also ask him if he can help his mama get out of the house on time.
On the talk-back, it's harder. I'd recommend remembering to not take it personally, as the button-pushing becomes easier and you both get stressed. Often but not 100% what works is reminding when this behaviour emerges that "I don't like that kind of talking" or "That's not the way to ask for something, that's not the way to talk to your mama", etc but have to follow up with what privilege will be removed if it continues and have to follow through on those ultimatums. Fortunately, my son's preschool teacher is in sync with that approach so although he still makes attempts the behaviour doesn't last long.
Lastly, your son may be acting out a problem and not be able to articulate fear or frustration or whatever emotion is happening. Remember to be present for him even while disciplining. Social life can be very rough for kids just like work life for us can be stressful. Try to help him find a path to comfort that's more effective than acting out. Provide him with the words he needs to manage situations at school or at home when he's telling you of difficulties he has with the other kids or siblings.
Good luck. More challenges to follow for sure so take it in stride (this is the practice run for teenage years!!)