@90 50 I saw that you had mentioned earlier about Luke dying and his metal hand. I think that's an interesting convo too, good point. I've watched it, and first it's hard to tell, as the scene is from behind and the music is playing loudly, so maybe the hand is there, maybe not, we just don't see it, too vague!
That stated, I do think Rian Johnson did admit at some point, although I'm not going to look up the source right now (about 8 beers in), that he screwed up and should've added a metal hand clinking.
But that leads into a ton of other thoughts, like maybe the hand is a part of him, Obi's saber was separate so didn't join him when he was killed. Or Obi-Wan's robe stays, but in his Force projections with Luke, he's wearing his robe. Yoda dies, his clothes, belt, necklace leave with him but not his blanket, which by the way is Qui-Gon's robe. Yep, Yoda took Qui-Gon's robe and made a blanket out of it. So why do the clothes, belts, necklace and stuff go with them, but not the robes. And then Anakin force ghost is just a whole mess. Dude lost his arm while he was a Jedi. Obi took the rest. But force ghost Ani is complete
I think Lucas and Rian both admitted they screwed up, so it's a mixed bag of what can happen