@Yeh Essentially it is extremely likely that there will be differences between the two. Whether it's dialogue or liberties taken with the plot, but yeah I would never count on the light novel and manga being cut and paste. Which is more or less the issue here. A bit of a tangent but sometimes the manga merely acts as a pilot to promote the light novel. So the manga could have like one volume to get people into the story. You see that kind of thing happen with anime and manga too.
I've even come across a series where the anime, manga, and light novel were all vastly different from each other. Different plots, different endings, more characters, etc. Pretty much the reason why I started reading manga and light novels in general. It's because I expect there to be differences between them.
I'm also not a huge fan of just using someone else's translated work like this even if there were similarities, but I don't really expect you to share the same opinions or anything. I'm sure someone else could go more in depth or explain it better, but in this case, I wouldn't be able to trust what I am reading, so I'll wait for TZdY's releases.