Hi and welcome to the mesage boards. I am sure you will find a lot of help on here , just as I have over the past few months. I moved your post here, I hope it is the appropriate place!
From looking at your routine, I really don't think any solids would improve the sleeping situation. Milk is the most important at this age, foods are really just an add on.
I have noticed though, that although she gets good naps during the day, she has a very long period of wakefulness from 2 to 7 pm. My lo is just starting to handle that amount of time well, and he is 16 months! So she could be going to bed overtired which tends to make sleep very restless and interrupted. And then she is just getting used to sleeping on her own, a lot going on there. There are some sample EASY routines at the top of this forum for children of the same age, please take a look there. I am sure others will be able to help tweak your routine!
Another thought I had is that when solids are first introduced, it is typically for breakfast or lunch, so that if they have a reaction to something they ate, it doesn't disturb night sleep. Has your paed given the go ahead for eating dairy ? If she is eating a lot at this meal, it may be causing her to reduce the amount of milk she takes in at 6:45 feed. The milk is really what sustain them, so you might consider doing the solids earlier in the day.
All the best, Michelle