Hello!! You are so sweet to rescue this lil one. She sounds like a sweetie that needs some guidance. Chances are, with all the methods you have tried, the crate is not going to work for her. Snickers had MASSIVE sep anx (would pee and poop in confinement) and we tried everything but only 1 thing ended up working for him. We bought Snickers a baby play pen that is for human babies. It was about 3ft by 4ft in area and about 5-6 inches off the ground. It had all mesh sides so he could see out and we put blankets and toys inside for comfort. We put this playpen next to a window and waited to see what happened. The point of being able to see out the window REALLY soothed Snick, we live about 1/2 a mile from a main road and he could see the cars passing by. Something to occupy him. Now, we did not get an immediate result, so we started by putting homemade belly bands on Snick and he did pee in them for about a week and then starting holding it. It worked! He did know we were leaving when he was put in the pen (so be sure to out yours in the crate/playpen/whatever you use WHILE you are HOME so she doesn't associate the space to when you're going to leave her.) After a week or so we removed the belly bands and he got it. About 4 months later, we would leave him in the house for short amounts of time and eventually made the times longer and now he has free reign of the house and has been great. Snickers just turned 1 about 2 weeks ago.
Hope this might help, just another idea
Good Luck
Snick & Viv
Ps. DO NOT give your dog attention 5 min before you're going to leave and after 5 once you have returned.