5. ian hendry - he only left his wife. didn't kill anyone
4. the businessman who couldn't die - he didn't kill anyone
3. joan collins - killed her husband. not sure why. she was younger and too hot for him
2. the major who ran the home for the blind. cold hearted bureaucrat
1. the young guy who drove peter cushing to death.
Most likely married an older rich man and didn't have the patience to wait for him to die of natural causes so she could inherit the money. Either that or she did plan to murder him all along.
I like that you call Elliot a boy. He is technically a man but he is spoiled and acts like a boy. Like a boy, he vandalizes his neighbor's garden just to frame Grimsdyke for it. We also don't see him ever go to a job of any kind. Plus he lives with his father which further implies that he doesn't have a job.
I figured he was supposed to be something like early 20's but he could have been older and looked young for his age. The actor who played him was 30. He acts basically like a bullying teenager except most teenagers aren't even that cruel and heartless. He was a rich snob and I'm unsure if those kinds of people do work (in the traditional sense). I would guess he was probably waiting to inherit his father's fortune.