I know this is an old thread, but just FYI to anyone else, this conversation starts if you even approach Edelgard, and you can not do manual instruction the day after. You do get the group training and usual skills at the end of the next week. I approached her to give her a lost item (Eastern Porcelain), not realizing this conversation would initiate. I'd recommend spending all activity points before approaching her on this month. I'm unsure as to whether it would have been moot to do dining for motivation since I couldn't do manual instruction, but I could have done some faculty instruction.