Hallucination should block touches of death (via an out-of-body experience) even if it’s being suppressed by wielding Grayswandir.

You can get some rare intrinsics by eating artifacts that confer them. For instance, eating Excalibur could give level-drain resistance, or eating Grayswandir could give hallucination resistance.

The chance would be much less than 100%, possibly even lower than the standard odds of getting an intrinsic from eating jewelry.

To be more true to its source material, Grayswandir should deal double damage only to crossaligned targets rather than all targets (though this would not likely have a huge effect since most wielders of it are lawful and few monsters are lawful).