I'd argue that Clone's "creature must be alive" is covered by magic jar. The body is dead, but the creature's soul isn't.
This is based off (a) the rule of cool, (b) when something isn't abusive and is ambiguous, bias in favor of permitting it, (c) the spell is about rehousing a soul in a duplicate body, so the state of the soul is fair game.
Now, biologically dead bodies cannot grow clones, but this isn't biological cloning. I wouldn't permit a sufficiently decayed body to contribute to this, but either a recent corpse or one protected by gentle ripose is fair game.
This is based off (a) the rule of cool, (b) when something isn't abusive and is ambiguous, bias in favor of permitting it, (c) the spell is about rehousing a soul in a duplicate body, so the state of the soul is fair game.
Now, biologically dead bodies cannot grow clones, but this isn't biological cloning. I wouldn't permit a sufficiently decayed body to contribute to this, but either a recent corpse or one protected by gentle ripose is fair game.