Darth Venal said:

I don't get why the conversation would take place in Ben's house at all. On Tatooine, before Luke goes to Jabba's Palace, sure. But why Ben's house? I don't think a Force "ghost" would have any reason to cling to its living domain, he's not a ghost in that sense, surely.

It's placed there for a number of reasons it bookends the start of Ben talking about Anakin in ANH so there's a visually poetic reason for it being in the same place, Ben has the tools for building the new lightsaber, it's a convienent out of the way place for the heroes to meet up and as I described before it makes the discussion serve a purpose beyond just closing the door on the inconvienient Han, Luke, Leia love triangle.

TMBTM said: Maybe put the scene into a Jabba's prison cell... after he killed the Rancor? Coud be easier to do cause Dagobah is kind of a dark place too. (I did not think about all the consequences on the other scenes though, just a quick thought).

The problem there is that there is no photographic evidence for what the cell Luke is kept in looks like, it serves no purpose because Luke has already pressed ahead with the rescue and he is now, as far as the audience is concerned, is as much of a mess as Leia is and it slows down the story just as it's picking up.