Re: Pump weaning
Yes, you'll be able to nurse on demand when you're still together. I haven't pumped for Beatrix since December and she's still nursing on demand overnight and on weekends.
For pump-weaning, just back off slowly. I phased each pumping session out over a week and then pushed the other pumpings later in the day.
As far as cow's milk, you could start with one bottle a day, or even slower. With both of my girls, I had a freezer stash that we used up when I stopped pumping, so we phased the milk in. They were both taking about 8 ounces of my milk at that point, along with solids, so I just asked that my DCP not give more than that in a day.
Lilah 10/08 nursed 25 months
Beatrix 01/11 nursed 30 months