If memory serves Obi-Wan trained Luke in SW and then Yoda trains him in ESB…if that’s true that could only mean…
It means they did not rehash Obi-Wan from ANH but they did Yoda from ESB. I do not think anyone claims they rehash every single concept. They only rehash most of them.
Based on the fact that she will be trained in the 2nd movie and on some new planet…which is barely the premise of the training. We don’t know what type of teacher Luke will be, what he will teach her, how she will react to the teachings and even if she will complete her training.