Just wanted to sympathise and offer something that helped me. I read, somewhere, that part of this behaviour is about the child looking for boundaries, because the boundaries (rules and consequences), make them feel safe- ie- they give them a structure in a world that can be confusing to them, and a world where they have no framework for their emotions. Remembering this sometimes (but certainly not all the time!) helps me when DS acts up in this way- I remind myself that he not so much being naughty as "bumping into the walls" to make sure they are there. It can also be an incentive to try to be consistent in my approach and consequences/ discipline, whatever method you choose. I will openly admit, though, that my DS's behaviour is mild in comparison to your DD, so I would never presume to tell you what is going to work!

But I also really wanted to offer sympathy- it is so, so hard when you and your partner disagree on parenting. I find it can causes a previously unheard of level of friction because you both think you are doing the right thing by your child, and you both think the other person is "hurting" (used loosely) the child and because you love them so much, that is very painful and anger inducing. You know all this, of course, and you would also know all the standard answers- communicate, get on the same page etc- but none of that makes it any easier or less hurtful, and so I feel for you. For what its worth, I think trying to allow your DD to take responsibility for tasks she can handle herself is a wonderful idea. So much of toddler's tantrums seems to be about not feeling like they have control over anything. The more choices (within reason) I can give DS, the happier he seems to be. I can see where your husband thinks its letting her have her own way, but you are still controlling the limits of her choices- eg- you let her choose what to wear within a certain range of clothes or choose her lunch out of 3 selections.

I hope things improve for you soon!