Miss Earnshaw's mysterious Second Class List

A member of the Association Francaise du Titanic owns a very strange document, which he inherited from Miss Earnshaw. At the time she gave him it, he did not thought that it would be the source of many questions and just accepted it.
Miss Earnshaw saved from the Titanic, or later bought, a "Second Class Passenger List per Royal and US Mail SS Titanic", on which she ticked different names and added notes. These names and notes are:

Bateman, Mr Robert J.: 17 4 E
Butler, Mr Reginald: 97 E
Chapman, Mr Charles: 130
Chapman, Mr John H.: 17
Carbines, Mr William: 18
Fox, Mr Stanley H.: 236 E
Faunthorpe, Mr Harry: 286 E
Gill, Mr John: 155
Giles, Mr Ralph: 297 E
Givard, Mr Hans K.: 305 E
Greenberg, Mr Samuel: 19 E
Hickman, Mr Leonard: 256
Hoffman, Mr and two Children: 15
Kantor, Mr S.: 283 P
Kvillner, Mr John Henrik: 165 E
Leyson, Mr Robert W. N.: 108
Louch, Mr Charles: 121
Mack, Mrs Mary: 52
Milling, Mr Jacob C.: 271 E
Norman, Mr Robert D.: 287 E
Nasser, Mr Nicolas: 43 E
Stokes, Mr Philip J.: 81
Swane, Mr George: 294 E
Weisz, Mr Leopold: 293 E

This water stained document hints at the graves of Titanic victims in Halifax: for instance, "15" is the number given to Mr. Navratil's grave (Hoffman was an assumed name). Do all numbers fit a grave or a body number? Why did she tick names on a Second Class list as she herself was a 1st class passenger? Where did she find this Second Class list? Why is it so water stained? How did she meet so many Second Class passengers? What do the second number and the letter mean? Miss Earnshaw passed away and never gave out the answer to this questions...