1) This will not affect the baby.
2) The chances of vaginal delivery after 1 previous caesarean section (CS) depends upon the indication of the first CS, whether or not you were in labour before the first CS, and the progress of the current pregnancy. If this pregnancy is progressing normally, and you do not have a contracted pelvis, and the first CS was due to a non-recurrent indication like fetal distress, you have a 75% chance of a vaginal delivery in this pregnancy.
3) If you undergo a repeat CS, the umbilical hernia can be repaired at the same sitting, if the first CS was done by a longitudinal incision. If it was done by a transverse incision, surgeons normally prefer to do a umbilical hernia repair after 6- 8 weeks of delivery, as that operation site would be different, and the muscles regain their tone by 6- 8 weeks. It is good to discuss this with your doctor before delivery time.