Thanks for the advice! I tried Aptamil with our son and he seems to like it - at least enough to drink the 1-oz that we spoon-fed him, mashed in banana. After the failure with Nan-Ha and Meiji, I thought I would play it safe and instead of offering it in a bottle, we gave the milk mashed with fruit so that it was like a new food, instead of breastmilk replacement. Not sure if it's the method or the milk, but either way, it seems to work.
I plan to increase the milk amount, but will continue to offer it with fruit (banana, papaya) so that it will be like a meal instead of a bottle to him.
It's a great relief as I still plan to breastfeed him whenever I'm home (mornings and evenings) but this way, I may not need to pump as often at work.
Thanks ever so much everyone!