Congratulations! How very exciting.
Some women have had great results with domperidone and pumping. We just don't know who will and who won't. If you're opposed to using the birthcontrol pill (and I certainly understand that), then taking domperidone, herbs, and pumping is a good option, and certainly better than no preparation at all! Pumping every 2-3 hours during the day with a good double-sided pump (like Medela's Pump In Style) for about 10 minutes tells your body that it's time to start the milk-making process. The risky part is that it's a few months of hard work (pumping) and there's always the possibility of the adoption falling through. However, you know your own situation best and need to make that call. For me, I always figured I could donate the milk anyway, and have done so.
As far as your Mum's milk, it's certainly going to be infinitely better than any imitation breastmilk from a cow or bean, you know? It also might be a tough decision, but it's a good option. We don't know if her supply would increase much, but it might, and it's something to consider.
Kerri