At this stage in your pregnancy it's fine. If you were in your first trimester I would have said wait a while, but your baby is done forming stuff that might be at risk earlier on.
Yes it's fine. :) I color once a month
Oh yeah Ive been dying my hair black for 4 yrs and wasnt about to have light brown roots and black ends for 9 mths lol
Its totally fine. Like the dr says-ventilated area!