There was one speaker on the right front door. It is of no use since when one does the ICE purchase, there would purchase of speakers in pairs.
speakers are coaxials.
Everybody suggests for component speakers at the front.
At the rear there can be oval coaxials or component speakers depending on the budget.
A note : component speakers need more power to drive them. So if you are not opting for an amplifier , go for the 4 ohm speakers. If you decide upon an amp, the 2 ohm speakers could be preferred for better bass (all subjective )
brands preferred focal,morel,JBL, power bass, hertz etc.
Important : do not rush in for the ice purchase.
Move around in more than 4 to 5 shops. Get the feel of what brands they sell, audition them (only for their sound signature since the ambience inside your car would be different than the speakers at the audition) . Check out how they perform on other car they might be performing the ICE installation.