Whilst you are a LPR the PD is more important that when the I 130 is approved. I
Student visa well that depends on the circumstances, obviously lots of Nigerians do get Student visa's. What does she want to study, can she afford it?
My guess is that any children would be USC's, CRBA, but if they are not you could file an expedited I 130 if they could not be included on a F2a because you had Naturalised.