P.G.
don't know about the teeth thing - though I did google and saw that this is normal - some moms said their kids got their first teeth at 13 months.
My son has a HUGE head. We didn't have to do the MRI stuff for several reasons, his head is in proportion to his body - he's just freaking big and his head reflects that. Also, he met his developmental milestones so the doc wasn't very worried about fluid on the brain as that would impede my son meeting developmental milestones.
I would ask about the developmental milestones to see if he's on target before pulling out the big diagnostic guns. Good luck!