When a baby is hungry, they'll eat anything. I was unlucky and ran out of milk around 4 months. I wanted to feed full term. My lack of milk began with my breast pump. My baby could get enough milk out of me to feed himself, but I couldnt pump hardly anything, therefore when I was at work my husband had to feed our son formula. Then when I returned it was breast milk. When getting formula, he made a mad face while eating. I believe he understood that daddy gave formula and mommy gave milk. When I ran out of milk completely, my son already had the taste for formula and did not rebel at all.
I would suggest, having your husband feed the formula a few weeks prior to the switch. Like we did, it was swift and easy. AND when he was off the boob, he was off the pacifier. The pacifier is meant to help them increase suction when on the breast. If they are not being breast fed, the pacifier is unnecessary.