You should have 3.5” (8 ohm 15w) in the dash, 6”x9” (4 ohm 15w) in the door, and 6.5” (4 ohm 15w) in the rear deck.
NOTE: the dash and door speakers are wired in parallel on the front channels, and each front channel will have an effect nominal impedance of 2.67 ohm at the head-unit, with the door speakers getting the majority of the watts sent down the channel.
You will want to look for replacement speakers with similar nominal impedance values or if shopping for composites for the dash/door, their overall listed impedance should be 3-4 ohm. (The Kenwood component set mentioned above is 4 ohm IIRC).
Speakers that have a lower RMS wattage will be a good fit when using the factory head-unit as the amplifying source, as is obvious by the factory speakers’ listed wattage of 15w. If you ever plan on adding an amp to power the speakers, a higher RMS wattage on the speakers will be desirable, but they may not sound the best while still powered by the factory head-unit.