Home Counties (-ish) then — not quite RP … less ‘brittle’ … but not altogether dissimilar.
What makes you think of them as sinister?
Elba’s is ‘East End’ — what many people think of as ‘Cockney’ … and, in his case, is.
I don’t dislike the others’ accents … although I find McKellen and Stewart sound just a little forced … and can quite comfortably speak not dissimilarly myself, when in the right company … but I‘m equally at home with Elba’s — although I don’t have that accent myself, I’m a bit of a socioeconomic chameleon and can drop into a more ‘working class’ mode according to what will best set my interlocutor(s) at ease 😉
I quite like Morgan Freeman’s voice myself — it’s rather soothing and not as ‘twangy’ as most U.S. voices, I find.
I don’t object to Jones’ accent but it’s a bit more nasal … not unpleasant, but not quite as pleasing to my ear — kinda like the difference between Fry and the other two, it sounds just a little too much like the result of elocution lessons rather than a natural voice.