

That’s most Abrahamic religions for reference a beheaded Christian can’t go to heaven either.
That said the number one rule in Islamic burial is no cremation like… A bomb is incineration. It’s not a total bar but if you believe in such things you’d be having conversations trying to justify why you are the way you are. Getting disassembled is probably a pretty good excuse but still.
Yes, though the way you are buried in Islam is extremely important. No, it’s an impediment to admission, like an incredibly hateful speed bump.
Depends on whom and when. Cromwell for example was exhumed, dismembered and displayed specifically to spite him. But yes In the middle ages if you were basically being given extra steps to get to heaven.