It can all seem so complicated, can't it? It's great that your DD is off to such a good start. According to the majority of the world's pediatric experts, breastmilk and/or formula should be your LO's main source of nutrition until she's closer to 1 yr of age. Solids are only for practice and nutritional supplementation and shouldn't take the place of breastmilk or formula...they simply aren't as nutritionally complete. With bfing, it's hard to strike the right balance. She should still be nursing at least 4-5 times per day and you shouldn't see a decrease in the time she spends nursing or her interest in it. I wouldn't try to drop the df or any other bfs until the night feeds are gone again. Otherwise, it might be much more difficult to eliminate them.
I'm wondering what's causing the nightwakings (I'm sure you are too!). Some possibilities...believe it or not, too many solids can make her hungrier! I know that's counterintuitive, but no solid food is as calorie-rich as breastmilk or formula. If there's a possibility that she's been taking less breastmilk in favor of solids, then she may not be getting enough calories and that could be a sign to cut back on solids. Could also be tummy upset or gas from starting solids too (sweet potatoes for dinner always gave Tyler gas during the night). When she wakes at night, what tells you that it's hunger? Is she taking full feedings? If you try to comfort her instead of feed her, will she go back to sleep? If so, is she up again shortly thereafter?
Sometimes, upping solids does help, especially if you haven't noticed a decrease in her nursing. Honestly, it comes down to experimentation to figure out what's going to work...sometimes cutting back on solids, sometimes increasing them. Try one, give it a few days, and see what happens. And let us know how it goes!