R.M.
It is probably going to be easiest to mix milk with pumped breastmilk at first if you can do that. I didn't do this at first, and found out later that I should have. It took mine a few months before he would start accepting the cows milk. I was still nursing but had cut way back, so I just wanted him to get used to milk in a sippy. It took a while. But one day he just took it. Better to do it gradually if you can. Like 75% breastmilk to 25% cows, then after she is taking that ok, 50/50, then 25/75, then all cow.
If the transition takes a while before she willingly drinks it, giving her other dairy to cover the gap will be good. Cheeses, yogurt, broccoli, and fortified oj are a few good milk substitutes. Also, organic supposedly tastes closer to breastmilk than regular store brand, so you could try doing organic milk. And she might take it just fine.
She NEEDS whole milk until she is two. It is very important for their brain development that they have the good fats found in whole milk, unless you are careful to give other fats healthy fats regularly, the way vegans have to. No 2% until after 2. Yes, you will need to get two kinds of milk if you drink something else. And yes, they can get anemic if they have over 32 ounces a day. They should have 16-24 oz a day. Our sippies are 8 oz sippies, so I make sure he gets between 2 and 3, no more. That probably won't be an issue at first.
As far as dad goes, you will have to let him make mistakes. Don't nag at every little thing he does that isn't the same as you. But it is time for him to step up and be a dad. I'm sure he doesn't really want to change a diaper. I don't either always. But that is his job and it has to be done. Let him watch you for a few days and see how you do it. Are you able to keep in touch by phone with him if he has any questions? That will help put your mind at ease. I know this is going to be a hard transition for you, I'm sorry. I had to do it at 15 mos when my husband lost his job and I hated it. It gets better though. You are right- you are being a good parent and trying to give her the best life possible. That is most important. Good luck!