if there are two distinct seating areas then two fans would be appropriate. i don't like fans over dining tables (i dont like a breeze on my food, and they are never as pretty as a chandelier) but if you have a living room and family room all in one space, then two fans is fine.

Do you need fans? Yes you can put two of either in a large room if it has a regular height ceiling the lights might work if a really high ceiling it will require dropping lighting so it actually lights the space Make sure the lights are the right scale for the space if going with that option