Thanks for your kind words and excellent feedback!
I totally agree, the game doesn't lend itself well to replayability. The multiple endings exist because it is fun to have the possibility of different outcomes but I wouldn't feel compelled to find them all as the gameplay remains mostly the same each time. The 'default' ending is certainly the one I expected most people to get but exploration might lead to discoveries that could get a player an alternate ending on their first playthrough, which I like to reward :)
Dialogue options and answers are actually not a deciding factor in the ending you get (though can act as clues at one point, in a way).
I did debate telegraphing the steps to another ending more clearly to aid players, but ultimately decided not to encourage the 'need' for multiple playthroughs because, as mentioned, the gameplay isn't compelling enough to warrent them haha!