Thanks for asking on HealthCareMagic. I have gone through the query carefully. Let me tell you that the inner lining of the ventricles of the brain (that contain CSF and provide nutrition to the brain), is friable and can get damaged easily. In case of
meningitis which is an infection of the coverings of the brain, the situation could get further complicated giving rise of blockage of the
drainage system of the CSF and due to the built up of the pressure give rise to
hydrocephalus. Even if the infection gets controlled, the blockage is likely to persist and hence the hydrocephalus requires shunting.
The seizures are caused due to
nerve stimuli short circuiting in the damaged parts of the brain (where the damages may be caused either due to the prematurity or due to the infection). The hiccups could actually seizures that are being mistaken as hiccups but are actually aberrant brain stimuli that are causing the diaphragm to contract forcibly. Hence, they are likely to be not triggers but effect of seizures.
After birth, the weight of the baby generally comes down but resumes subsequently so you need not worry about that.
I hope that helps. Feel free to revert back in case of further queries if any.