The information content is the same - James's location. Other prepositions can be used and they can indicate direction. Up at James's house might suggest James's house is uphill. Down at James's house might suggest downhill. Over at James's house isn't as definite but we might get the idea that James's house is across the street or something like that. Basically, however, they don't usually add much actual information. They do make speech sound less bare and warmer. 'Over at James's house' feels 'friendlier' than 'at James's house'.

The information is exactly the same. However, communication of information is only a part of what language does. Language also lets you communcate what is going on inside your head. "Over" means above. A bird flies OVER your house. In sentence #1, the speaker mentally flies over James' house and looks down upon it. I'm not saying he imagines himself to be a bird, but in his mind he travels to the spot before he names it. It makes his language more interesting and more human.

There's really no difference. I'm not sure what you'd call 'over', but there are a lot of modifiers like it that don't really mean a whole lot. at james' house over at james' house down at james' house up at jamess'house All mean basically the same thing.

Died ？isn’t?