You can... what are you trying to accomplish by doing that?
Studies have been pretty conclusive that it does not help the baby sleep longer.... we tried it anyway and probably just ended up making our fat baby fatter.
Yup, you can. But they don't recommend the cereal in a bottle because I guess it poses a choking hazard. We never tried with Sophia, so I don't know. I've heard it is more likely to upset their tummies than help them sleep longer too.
When baby is on solids, I've heard of Mommies mixing their breastmilk with cereal and feeding it with a spoon.
However, mixing it does help the baby accept cereal better...