Hi there!
I think there are a few things going on.
If she's showing signs of readiness for solid foods you can continue but for some babies the rice cereal is hard on their tummies.
Is your baby ready for solids?. You can try pear, squash, sweet potato,which tend to be more gentle on their tummies. Also I would start with morning and then a lunch meal rather than before bt as solid food in the tummy may cause more discomfort. If she's not quite ready yet, then stop feeding solids and wait a 2-3 weeks and try again.
Looking at your routine, her A times are quite low so you might want to bump them out so that she's up for 2.25 to 3 hrs.
Average A times- BOOKMARK ME! . The other thing that starts to happen around this time is dropping the CN as the A times are increased. Her nw's may be caused by having too much DT sleep.
All about the 3-2 transition- 5/6 monthsLastly developmental things like rolling will also cause disruption in sleep so give her lots of time to practice during the day and as she perfects her skills, this will be a non-issue during the night!
HTH