What were the motives of the suspects in The Hound of the Baskervilles?

Several suspects are considered in the case being investigated by Mr. Sherlock Holmes and Dr. John Watson. Their prime suspect is Mr. Stapleton, who is the estranged nephew of the late Sir Charles. He owns a very large dog, who would be capable of leaving the sort of large footprints found near Sir Charles' body. Mr. Stapleton, though having grown up distant from his family, would be next in line to inherit his family's fortune...

Several suspects are considered in the case being investigated by Mr. Sherlock Holmes and Dr. John Watson. Their prime suspect is Mr. Stapleton, who is the estranged nephew of the late Sir Charles. He owns a very large dog, who would be capable of leaving the sort of large footprints found near Sir Charles' body. Mr. Stapleton, though having grown up distant from his family, would be next in line to inherit his family's fortune in the case of the death of his uncle (Sir Charles) and cousin (Sir Henry.) 

There are also Mr. and Mrs. Barrymore, who work as servants in the Baskerville home. They would essentially inherit the estate as its caretakers if Sir Henry were to die and no heir came forth to claim the fortune. They act rather strangely in the story, which brings us to our next suspect. Mrs. Barrymore's younger brother, Selden, is the escaped Notting Hill Murderer. He would not really have much motive in killing the Baskervilles beyond satisfaction of a morbid desire for murder, and perhaps some theft of valuable goods.