Dwarf refers to a person with one of several varieties of a specific genetic condition called dwarfism. A dwarf has disproportion of body parts. This is generally caused by a genetic or nutritional disability. Any adult human below the height of 4'10 (147 cm) is considered a dwarf.
One Piece has a great story and does not have a lot of filler episodes.
The one problem I can think of with a 2 piece is that stray urine streams can get into the joint between the tank and bowl and fester. A 1 piece eliminates this. 1 piece tends to be more expensive. You also tend to be more limited with 1 piece in terms of choices.