Bibbity
Can the new owners not have the body moved upon purchase?
Professionally of course. Not shovels and skips etc.
If that was a possibility and I did want the house I would offer low and do that.
No, the relatives would object, they decided to carry out the disceased’s wishes and it was legal.
At some time in the future an owner could apply, probably to a court to move the body, if no relatives objected it could be done I’m sure - a financial inducement would help.