Actually, since the Rosie models have rivet guns, these Big Daddies were named for Rosie the Riveter, an American character during the 1940s, representing the women entering the workforce during World War 2 [link]
This is going to sound REALLY, REALLY nerdy but....you've got the weight about right. One of those old diving suits weighs between 250 to 300 lbs, add to that the 300 or so pounds of the person in the suit. Rumblers, Alpha Series, and Rosies would be roughly the same weight, while Bouncers would be considerably heavier. Big Sister, on the other hand, with her equipment and everything would likely weigh in around 200lbs.
Perhaps its because they are killing machines, they leave behind pools of blood in their wake. If viewed from a Little Sister perspective, then all pools of blood are seen as piles of roses. This is due to their psychological conditioning that makes the Little Sisters see Rapture as paradise instead of hell and angels instead of dead bodies.
In big daddy high school everyone makes fun of him for his name,He eats alone at lunch, he is always being made fun of the popular bigdaddys like delta and sigma. He asked a big sister cheerleader out but she laughed at his face and called him retarded for actually thinking they will be together. His little sister is embarrassed to be seen walking around with him. He lived like this for a long time until he fucking snapped! He goes in the school with mines and a fully loaded rivertgun he starts shooting every bigdaddy he sees. He goes on and kill delta and sigma due to a proximity mine then he grabs the big sister that rejected him and breaks her spine! Soon the lancers who are cops come to stop Rosie. Rosie looks at all the lancers that are outside. Soon he detonates all his mines which are all on the glass. Soon water comes gushing in! Everyone dies. Then a tunnel breaks due to the sheer force of the explosion. Jack who just got his electro bolt plasmid sees that tunnel collapse before atlas tells him to use the one two punch on the splicer. tunnel collapse. That is why jack dident see any lancers or rumblers thats because they all died and where being remade in secret. ......I really gotta stop seeing school shootings.