All TILES are 16x16, but not all sprites are. So grass, water, cliffs, fences, crops are 16x16 but the buildings are not made out of tiles, the characters are 20x16 and come in a 32x32 layout and trees are 32x32 for example.
The furniture is the same as in it is based on 16x16. So the flooring is 16x16 but wallpapers 32x16 or a rug can be 48x32
Every pack has a free version, so I would go ahead and try that first if I were you.